Provencal Acorn and Butternut Squash Gratin Casserole: The Ultimate Thanksgiving Side Dish Recipe
Prepare to elevate your holiday table with this exquisite Acorn and Butternut Squash Gratin Casserole. Crafted in a delightful Provencal style, this dish features two beloved winter squashes, deeply flavorful whole roasted garlic, tender chunks of potatoes, and a generous layer of Gruyère cheese that bakes into the most irresistible golden-brown topping. It’s truly a standout Thanksgiving vegetable side dish that promises to be unforgettable.
Much like our popular Potato Leek Casserole, this winter squash gratin offers a rich, decadent, and incredibly satisfying experience that beautifully complements any meal, from festive holiday feasts to comforting weeknight dinners.
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The Inspiration: A Culinary Journey to Provence
A few years ago, I discovered “The New Classic Cookbook” by Saveur, a treasure trove of global recipes. This remarkable book is packed with thousands of culinary traditions from across the world, ranging from authentic regional classics to inventive adaptations designed for ingredients readily available in the US. It was within these pages that I first stumbled upon a recipe for squash gratin that immediately captured my imagination.
The original recipe hails from the sun-drenched Provence region of France, traditionally prepared with a specific French pumpkin known as “potiron.” However, this particular pumpkin can be quite challenging to find outside of Europe. To achieve a similar taste and desired creamy, yet chunky texture, I found that a combination of acorn squash and butternut squash serves as a fantastic substitute. Their complementary flavors and textures create a perfect base for this Provencal-inspired dish, allowing anyone to recreate a taste of France in their own kitchen.
I experimented with this recipe several times, and while my husband adored it, I felt there was room for some personal refinements to truly make it shine. The version I’m sharing with you today is my unique take on this classic Provencal squash gratin, refined to enhance its flavors and textures. I genuinely hope you and your loved ones will enjoy it as much as we do, especially during the festive season.
What Makes This Acorn and Butternut Squash Gratin Truly Unique?
This Acorn and Butternut Squash Gratin isn’t your average, run-of-the-mill casserole. Its texture is completely distinctive and delightfully surprising, setting it apart from other gratin recipes. Instead of simply slicing the squash into uniform chunks, here’s where the magic begins: the squash is first boiled until tender, then roughly mashed with a potato masher, creating a wonderfully rustic and varied consistency that holds pockets of flavor.
But the unique qualities don’t stop there. This mashed squash is then combined with parboiled, chunky potatoes, adding another layer of heartiness and textural contrast. The mixture is further enhanced by an amazing medley of sweet, mellow roasted garlic, tender sautéed onions, and the earthy aroma of dried thyme. This thoughtful combination results in a texture that is simultaneously creamy and delightfully chunky, offering sweet notes from the caramelized garlic and onions, balanced by the warm, autumnal, and slightly herbaceous flavor of dried thyme. It’s a symphony of textures and tastes that truly defines comfort food.
And then comes the most pleasant surprise: milk is generously poured over the entire mixture, followed by a lavish sprinkling of freshly shredded Gruyère cheese. As it bakes, this Gruyère transforms into an irresistible, golden-brown crust, adding a nutty, savory depth that perfectly complements the rich squash and potato base. This golden crust is not just a topping; it’s an integral part of the dish’s allure, providing a satisfying crispness with every spoonful.
I am convinced that this dish will be the topic of conversation at your next Thanksgiving gathering or holiday dinner. It’s beyond delicious, deeply comforting, and simply unforgettable. Try serving this dish with a little fanfare and watch as your guests rave about its unique flavors and textures. If you’re looking for other impressive Thanksgiving ideas, be sure to check out My Favorite Thanksgiving Recipes for more inspiration.
Essential Ingredients for Your Provencal Squash Gratin
The beauty of this Provencal squash casserole lies in its straightforward ingredient list. All the items can be easily found at your local grocery store, making it accessible for any home cook. While Gruyère might sound a bit fancy, it’s a staple in most cheese sections and worth every bit of the investment for its incredible flavor and melting properties. Here’s a detailed look at what you’ll need:
- Large Acorn Squash: You can opt for a whole squash or pre-cut pieces. Acorn squash brings a slightly sweeter, nuttier flavor and a fine-grained texture to the gratin.
- Large Butternut Squash: Like acorn squash, pre-cut butternut squash chunks can be a real time-saver. Butternut squash contributes a deeper, richer sweetness and a creamier texture, perfectly balancing the acorn squash.
- 3-4 Russet or Yellow Potatoes: These potatoes add a crucial starchy element, ensuring the casserole is hearty and has that satisfying chunky bite. Russets will give a fluffier texture, while yellow potatoes are a bit firmer.
- Whole Garlic Clove, Roasted to Perfection: Roasting transforms sharp raw garlic into sweet, buttery, and mellow cloves. This essential ingredient infuses the entire dish with a subtle, aromatic sweetness.
- Sweet Onion: When sautéed, sweet onions caramelize beautifully, adding a layer of savory sweetness that complements the squash and garlic.
- Dry Thyme: A classic herb in Provencal cuisine, dry thyme provides an earthy, herbaceous depth that ties all the flavors together, evoking the essence of the Mediterranean.
- Milk: The liquid base for our gratin, milk creates a creamy consistency and helps form that luscious, golden-brown crust. Whole milk or 2% milk works best for richness.
- Gruyère Cheese: This Swiss cheese is non-negotiable for a truly authentic gratin topping. Its nutty, slightly sweet, and tangy flavor, combined with its excellent melting qualities, creates a bubbly, golden crust that is utterly addictive.
- Salt, Pepper, and Fresh Nutmeg: These fundamental seasonings enhance and balance all the flavors. Freshly grated nutmeg, in particular, offers a warm, aromatic note that beautifully pairs with winter squashes.
Once you’ve gathered these simple yet powerful ingredients, you’re well on your way to creating this magnificent squash gratin casserole! Remember, while this section provides an overview, please scroll down to the full recipe card for exact measurements, detailed instructions, and comprehensive nutritional information.
Step-by-Step Guide: Crafting Your Acorn and Butternut Squash Casserole
Making this delectable casserole is simpler than you might think, and the effort is truly rewarded with incredible flavor. Here are the easy steps to guide you through the process, along with some helpful tips:
Step 1: Prepare the Roasted Garlic. Begin by peeling off the papery outer layers of a whole garlic head, then slice off the top to expose the cloves. Place the garlic head in a piece of tin foil, drizzle generously with olive oil, and season with salt and pepper. Roast it in a 400°F (200°C) oven for approximately 40 minutes, or until the cloves are soft and golden brown. For excellent visual guidance, I often refer to the clear instructions on TheKitchn website. Once roasted, remove the garlic to cool slightly, but keep your oven at 400°F for later use.
Step 2: Peel and Cut the Squash. If you’ve purchased pre-cut squash, you can skip this step and proceed to boiling. For whole squashes, peeling can be a bit tricky. To make it easier, cut each squash in half and microwave it for about 2 minutes. This softens the skin slightly. Allow it to cool enough to handle, then peel and cut the flesh into roughly 1-inch squares. For more in-depth tips on buying, storing, peeling, and cooking winter squashes, consult my Ultimate Guide to Winter Squashes.
Step 3: Boil the Squashes. Place both the acorn and butternut squash chunks into a large pot. Cover them with salted water and bring to a rolling boil. Once boiling, reduce the heat to a simmer and partially cover the pot. Cook the squashes until they are completely fork-tender, which usually takes about 20 minutes. This ensures they’ll be easy to mash and blend into the gratin.
Step 4: Prepare and Cook the Potatoes. While the squash is cooking, peel your potatoes and slice them into 1/4-inch thick rounds. Place these slices into a separate pot of salted water. Bring the water to a boil, then reduce to a simmer, cover the pot, and cook until the potatoes are tender, typically around 10 minutes. They should be firm enough to hold their shape but soft enough to be easily pierced with a fork.
Step 5: Sauté Onions and Garlic. Finely chop your sweet onions. Heat a skillet over medium heat, add a tablespoon of olive oil, the chopped onions, and the dried thyme. Season with a pinch of salt and pepper. Sauté until the onions are soft and translucent, which takes about 5 minutes. Now, squeeze the sweet, roasted garlic cloves from their skins directly into the pan with the onions. Use a wooden spoon to mash the garlic cloves and mix them thoroughly with the onions and thyme, creating an aromatic base for the casserole.
Step 6: Mash the Squashes. Once the squashes are fork-tender, drain them well in a colander. Transfer the drained squashes back into a large mixing bowl. Using a potato masher, roughly mash the squashes. The goal isn’t a completely smooth purée; you want some delightful chunks to remain for that unique textural contrast.
Step 7: Combine Flavors and Season. Add the sautéed onion, thyme, and roasted garlic mixture into the bowl with the mashed squashes. Season with additional salt, pepper, and a generous grating of fresh nutmeg. Gently mix everything together, ensuring all the flavors are evenly distributed. Taste the mixture and adjust the seasoning as needed to your preference.
Step 8: Add the Potatoes. Once the potatoes are tender, drain them thoroughly. Add the parboiled potato slices directly to the bowl with the squash mixture. Fold them in gently so they don’t break up too much, maintaining their chunky texture.
Step 9: Transfer to a Baking Dish. Carefully transfer the entire squash and potato mixture into a 9×13-inch baking dish. Spread it evenly to create a uniform layer.
Step 10: Pour in the Milk. Evenly pour the milk over the entire squash mixture in the baking dish. This milk will seep down, creating a creamy texture while also helping to form the golden crust.
Step 11: Top with Gruyère Cheese. Generously shred your Gruyère cheese and sprinkle it liberally over the milk and squash mixture. This will become the star of your gratin topping.
Step 12: Bake to Golden Perfection. Place the baking dish into your preheated 400°F (200°C) oven. Bake for approximately 30 minutes, or until the casserole is bubbly around the edges and the Gruyère topping is beautifully melted, golden brown, and irresistibly crispy.
Step 13: Cool and Serve. Once baked, remove the gratin from the oven. Allow it to cool slightly for about 10-15 minutes before serving. This brief resting period helps the casserole set, making it easier to serve and allowing the flavors to meld even further. Enjoy your magnificent Provencal squash gratin!
Serving Suggestions: Perfect Pairings for Your Gratin
This Acorn and Butternut Squash Gratin Casserole is incredibly versatile and makes a stunning addition to any holiday table or a comforting centerpiece for a family meal. If you’re planning to serve this delightful gratin for your Thanksgiving or Christmas feast, consider pairing it with these impressive main courses:
- Fall Harvest Roasted Turkey Breast: The rich, savory notes of turkey are a classic match for the sweet and earthy gratin.
- Slow Cooker Turkey Breast: For a more hands-off approach to your main course, this slow cooker option pairs beautifully with the gratin.
- Maple Mustard Glazed Turkey: The sweet and tangy glaze of this turkey will create a harmonious balance with the creamy squash.
- Brown Sugar Pork Loin with Garlic and Herbs: The robust flavors of pork loin stand up wonderfully to the richness of the gratin, offering a delightful contrast.
For other occasions, such as a casual weekend meal, a special dinner party, or even a potluck, this gratin can be served alongside:
- Oven Roasted Chicken Legs: Simple, flavorful roasted chicken makes for an effortless pairing.
- Olive Oil Chicken Thighs: The Mediterranean flavors of these chicken thighs complement the Provencal essence of the gratin.
- Chicken Provencal with Shallots and Garlic: Lean into the Provencal theme with this aromatic chicken dish for a truly cohesive meal.
- Slow Cooker Whole Roasted Chicken: Another fantastic set-it-and-forget-it option that leaves you more time to enjoy your guests and the delicious gratin.
Recommended Equipment for Seamless Preparation
To make your cooking experience as smooth as possible, having the right tools on hand is essential. You likely already own most of these kitchen staples, but here’s a quick checklist to ensure you have everything needed to prepare this fantastic Acorn and Butternut Squash Gratin Casserole:
- Large Pot (or two): Essential for boiling the squashes and potatoes separately until tender. Having two can speed up the process.
- Colander: For efficiently draining the boiled squashes and potatoes.
- Potato Masher: Crucial for achieving that unique, roughly mashed texture for the squashes, leaving some delightful chunks.
- Large Mixing Bowl: To comfortably combine all the delicious ingredients before transferring them to the baking dish.
- Set of Knives: For peeling and cutting the squashes and potatoes, as well as chopping the onion and garlic. A sharp chef’s knife and a paring knife will be most useful.
- Cutting Board: A sturdy surface for safe and efficient prep work.
- 9×13″ Casserole Dish: The ideal size for baking this gratin, ensuring even cooking and a beautiful presentation.
- Cheese Grater: For freshly shredding the Gruyère cheese. Freshly grated cheese melts better and tastes superior to pre-shredded varieties.
Explore More Delicious Winter Squash Recipes
If you’re a fan of winter squash and looking for more creative ways to enjoy it, here are some other delightful recipes you might love:
- Roasted Butternut Squash Feta Pierogi: A savory and unique twist on traditional pierogi.
- Butternut Squash Beef Stew with Cinnamon and Pomegranates: A hearty and flavorful stew perfect for chilly days.
- Turkey Stuffed Acorn Squash: A complete meal in a beautiful squash bowl.
- Lentils Stuffed Acorn Squash: A delicious and wholesome vegetarian option.
- Truffled Butternut Squash Mushroom Soup: An elegant and earthy soup with a touch of luxury.
Acorn and Butternut Squash Gratin Casserole
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Ingredients
- 1 Large Acorn Squash Peeled and cut in 1 inch cubes
- 1 Large Butternut Squash Peeled and cut in 1 inch cubes
- 4 Medium Yellow Potatoes Thickly sliced
- 1 whole Roasted garlic
- 1/2 Large Sweet Onions Chopped
- 1/2 teaspoon Dry Thyme
- 1/2 teaspoon Fresh Nutmeg
- 1 cup Milk Whole or 2 %
- 3 cups Gruyere Cheese Shredded (about 0.5 lbs)
- 1 tbsp Olive Oil for cooking onions
Instructions
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Roast your garlic. Peel the paper off the garlic head; Chop the top of your garlic head and place the whole head in a tin foil, sprinkle with olive oil, salt and pepper, and roast at 400F for an hour. Once your garlic is roasted, remove it from the oven and let it cool off. Keep the oven hot at 400F.
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Peel and cut your squash (unless you purchased pre-cut then skip this step). In order to make it easier to peel, cut the squash in half, place in a microwave for 2 minutes; let cool before peeling; then peel and cut into about 1-inch squares;
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Place both squashes into a large pot with salted water and bring to boil; reduce to simmer and partially cover; cook squashes until fork-tender for about 20 minutes;
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Peel the potatoes and sliced them in 1/4 inch thick slices; place potatoes in a pot of salted water, bring to boil, then reduce to simmer, cover and cook until tender for about 10 minutes;
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Chop your onions, heat up a skillet, add some olive oil, onions and dry tyme; sprinkle with some salt and pepper and cook until onions are soft and translucent (for approx, 5 minutes); Squeeze out garlic cloves from the roasted garlic head and add them to the onions; break the garlic using wooden spoon and mix all together;
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Drain your squashes in a colander and place back into a large bowl. Using a potato masher, roughly mash the squashes;
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Add onions, thyme and garlic mixture into the bowl; add salt, pepper, fresh nutmeg and mix everything gently; check for seasoning and adjust as needed;
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Once potatoes are fork-tender, drain them and to the bowl with squashes;
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Transfer the squashes mixture into a 9×13 baking dish,
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Pour milk over the squashes mixture;
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Step 11: Shred your Gruyere cheese and place it on top of the milk;
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Transfer the baking dish into the preheated oven to 400F and bake for 30 minutes until bubbly and golden brown;
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Remove from the oven and let cool slightly before serving.
Nutrition
This post was originally published on November 1, 2018.
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