Sweet Potato Gratin
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Sweet potato gratin is a rich and creamy, cheesy side dish that’s the perfect side dish to any autumn meal. Layers of sweet potato, butternut squash and russets are topped with a creamy cheese sauce and baked until golden and bubbly.
Unlike some sweet potato dishes that are filled with sugary sweet ingredients, this one is decidedly savory with fresh thyme and two kinds of cheese.
Ingredients for sweet potato gratin
While a traditional gratin is just potatoes, this recipe adds flavor and color with sweet potatoes and butternut squash. Here’s what you’ll need:
- unsalted butter
- pancetta
- shallots
- garlic
- flour
- fresh thyme
- 1/2 & 1/2
- milk
- Parmigiano-Reggiano cheese
- baking or russet potato
- sweet potato
- butternut squash
- Gruyère cheese
- salt and black pepper
Step by step instructions for sweet potato gratin recipe
A food processor or Mandolin Slicer makes cutting the vegetables into uniform thin slices a breeze.
- Slice potatoes, and butternut squash into thin rounds, about 1/8″ slices. Bring a large pot of water to a boil and cook each vegetable separately for 4 minutes, or until almost tender. The vegetables will continue to cook in the oven.
- Preheat over to 375 degrees F.
- Melt butter in a medium saucepan over medium heat. Add pancetta and cook one minute. Add shallots and garlic and cook another 2 minutes, stirring constantly.
- Add flour and stir with whisk. Add thyme.
- Gradually add milk and 1/2 & 1/2 and stir constantly with a whisk over medium heat until slightly thickened, about 3 minutes. Stir in Parmigiano-Reggiano and blend until melted, about 3 minutes. Season to taste with salt and pepper.
- Arrange a layer of potatoes in a buttered 11″ x 7″ casserole dish.
- Continue to layer casserole with sweet potato slices and butternut squash.
- Spoon or pour cream sauce over potato mixture.
- Top with grated Gruyere cheese and bake at 375 degrees F. for 40 minutes.
- Preheat broiler. Broil 3 minutes or until golden brown. Cover with aluminum foil until ready to serve.
- Store in airtight container in the refrigerator for up to three days.
Substitutions
- Parmesan cheese is a good substitute for Parmigiano-Reggiano for a milder flavor
- Substitute a variety of fresh herbs for the thyme.
- Omit the pancetta for a vegetarian option.
Looking for more great options for your holiday table?
Any of these side dishes are a perfect for holiday dinners or special occasions.
Mashed Sweet Potatoes with browned butter and fresh sage.
Sautéed Root Vegetables or Harvest Squash Casserole
Lawry’s Creamed Corn or Lawry’s Creamed Spinach.
Old Fashioned Cornbread Stuffing or Wild and Brown Rice with Pecans and Cranberries
Roasted Brussels Sprouts with Red Pepper and Parmesan or Delicata Squash with Sage.
Don’t forget the Roast Turkey for your Thanksgiving table.
Sweet Potato Gratin
Ingredients
- 2 Tablespoon unsalted butter
- 2 ounces pancetta
- 1 medium shallot sliced, about 1/2 cup
- 2 cloves garlic chopped
- 5 Tablespoons flour
- 2 teaspoons chopped fresh thyme
- 1 cup milk
- 1 cup half and half
- 3/4 cup Parmigiano-Reggiano cheese grated
- 1/2 teaspoon kosher salt
- 1/2 teaspoon black pepper
- 1/8 teaspoon red pepper
- 10 ounces sweet potato peeled and sliced into 1/8" thick rounds, (1 medium)
- 8 ounces butternut squash peeled and sliced into 1/8" thick slices (about 1/2 medium)
- 1 pound russet potatoes peeled and sliced into 1/8" thick rounds
- 1/3 cup Gruyere cheese grated
Instructions
- Preheat over to 375 degrees F. Slice potato, sweet potato, and butternut squash into thin rounds, about 1/8″ slices. Bring a large pot of water to a boil and cook each vegetable separately for 4 minutes, or until almost tender. The vegetables will continue to cook in the oven.
- Melt butter in a medium saucepan over medium heat. Add pancetta and cook one minute. Add shallots and garlic and cook another 2 minutes, stirring constantly.
- Add flour and stir with whisk. Add thyme. Gradually add milk and 1/2 & 1/2 and stir constantly with a whisk over medium heat until slightly thickened, about 3 minutes. Stir in Parmigiano-Reggiano and blend until melted, about 3 minutes. Season to taste with salt and pepper.
- Arrange a layer of potatoes in a buttered 11″ x 7″ casserole dish. Continue to layer casserole with sweet potato slices and butternut squash.
- Spoon or pour cream sauce over potato mixture. Top with grated Gruyere cheese and bake at 375 degrees F. for 40 minutes.
- Preheat broiler. Broil 3 minutes or until golden brown. Cover with aluminum foil until ready to serve.
- Store in airtight container in the refrigerator for up to three days.
