Every Thanksgiving, I test one or two side dishes that aren’t the usual suspects. I love mashed potatoes and stuffing as much as the next person, but I’m always looking to bring something to the table (literally) that sparks conversation and curiosity. A few years ago, I made a Sweet Potato Gratin with Parmesan on a whim, just slicing, layering, and hoping for the best. The moment I pulled it out of the oven, bubbling, golden, and smelling like butter and sharp cheese. I knew it was a keeper. Since then, it’s become one of my Thanksgiving go-tos.
This sweet potato gratin isn’t the marshmallow-laden casserole some people expect. Instead, it leans savory, with thin slices of sweet potato baked in garlicky cream and topped with a crispy layer of Parmesan. It’s simple to prepare, big on flavor, and fancy enough to earn a spot on your Thanksgiving menu.
I especially love this dish for Friendsgiving. It’s easy to prep ahead, forgiving if you’re juggling oven space, and doesn’t need babysitting once it’s in the oven. Plus, the Parmesan crust always gets compliments, even from guests who think they don’t like sweet potatoes.
If you’re planning out easy Thanksgiving recipes, this gratin pairs beautifully with other fall dishes like these air fryer carrots or even these crispy boneless chicken thighs when you’re skipping the turkey. And when I want to keep the oven open for dessert, I serve this with air-fried sweet potatoes as a backup side for extra warmth.
Let’s get right into the recipe.
Sweet Potato Gratin with Parmesan Recipe
Ingredients:
- 2½ pounds sweet potatoes (about 3 large), peeled and thinly sliced
- 2 cloves garlic, minced
- 1½ cups heavy cream
- ¾ cup grated Parmesan cheese (plus extra for topping)
- 1 tsp salt
- ½ tsp black pepper
- 1 tsp fresh thyme (or ½ tsp dried thyme)
- Butter for greasing the baking dish
Optional:
- Pinch of nutmeg
- ¼ cup panko breadcrumbs (for extra crunch)
Instructions:
- Preheat the oven to 375°F (190°C). Butter a 9×9-inch baking dish or similar.
- Infuse the cream: In a small saucepan, combine cream, garlic, salt, pepper, and thyme. Heat gently over low heat for 5 minutes, then stir in ½ cup Parmesan. Remove from heat.
- Layer the gratin: Arrange half the sweet potatoes in the dish, overlapping slightly. Pour half the cream mixture over. Repeat with remaining potatoes and cream.
- Top and bake: Sprinkle remaining Parmesan and breadcrumbs (if using) on top. Cover loosely with foil and bake for 30 minutes. Remove foil and bake another 20–25 minutes until golden and bubbling.
- Let it rest: Cool for 10 minutes before serving . It sets nicely and slices beautifully.
Tips & Variations:
- Add sliced shallots or a pinch of cayenne for heat.
- Swap in Gruyère or sharp cheddar for the topping if preferred.
- Make it vegetarian by serving with blooming onion instead of meat mains.
Why This Gratin Belongs on Your Thanksgiving Table
There’s something about the balance of sweet and savory that makes this sweet potato gratin with Parmesan unforgettable. It’s bold enough to stand next to a roast turkey, yet comforting and familiar, just what a side dish should be. Best of all, it’s make-ahead friendly and reheats like a dream, which takes so much pressure off holiday cooking.
If you’re building a Thanksgiving side dishes board, add this to your lineup. It’s a little unexpected, totally satisfying, and always gets eaten down to the last cheesy bite.