Description
A comforting and elegant cheesy root vegetable gratin perfect for Thanksgiving dinner, featuring thinly sliced sweet potatoes, parsnips, and beets baked in a creamy Parmesan sauce and topped with melted Gruyere cheese and fresh thyme garnish.
Ingredients
Scale
Preparation
- 1 tablespoon unsalted butter, softened
Vegetables
- 1-2 long sweet potatoes (about 2 inches thick), peeled
- 3-4 large parsnips, ends trimmed and peeled
- 3-5 small beets, peeled
Cheese and Dairy
- 14 tablespoons heavy cream, divided (whole milk can be used as substitute)
- 4 ounces grated Parmesan, divided
- 1 ounce shredded Gruyere
Seasonings
- 1 tablespoon fresh minced thyme, divided plus more for garnish
- 1 garlic clove, minced
- Salt and pepper to taste
Instructions
- Preheat and prepare dish: Preheat the oven to 400˚F (204˚C). Grease a 3-quart baking dish with the softened butter to prevent sticking.
- Slice vegetables: Using a mandoline or sharp knife, slice sweet potatoes, parsnips, and beets into very thin rounds. Place each vegetable in its own bowl to keep them separate.
- Season vegetables: Pour 4 tablespoons of heavy cream over the sweet potatoes and parsnips each, and 2 tablespoons of cream over the beets. Add ½ ounce grated Parmesan and 1 teaspoon minced thyme to each bowl. Season generously with salt and pepper, then toss gently to coat all slices evenly.
- Prepare baking dish base: Pour the remaining ¼ cup (4 tablespoons) of heavy cream into the bottom of the baking dish. Sprinkle with ½ ounce of Parmesan cheese and the minced garlic to create a flavorful base layer.
- Assemble the gratin: Arrange the sweet potato slices upright on a bias along one side of the baking dish. Follow with a row of parsnips, then a row of beets. Repeat the layering pattern until all vegetable slices are used, creating approximately six rows of root vegetables standing on edge in the dish.
- Season and cover: Season the top of the arranged gratin with additional salt, pepper, and sprinkle the remaining Parmesan cheese over the surface. Cover the dish tightly with aluminum foil.
- Bake covered: Place the covered gratin in the preheated oven and bake for 30 minutes or until the vegetables start to soften.
- Add Gruyere and finish baking: Remove the foil, sprinkle the shredded Gruyere evenly over the top, and return the dish uncovered to the oven. Bake for an additional 18 to 20 minutes until the vegetables are fork-tender, the cheese is melted, and the top is lightly browned and bubbly.
- Garnish and serve: Remove the gratin from the oven and sprinkle fresh thyme leaves on top for a fragrant finish. Serve warm as a delicious side dish for Thanksgiving or any comforting meal.
Notes
- Makes 1 (3 quart) casserole.
- Nutrition facts calculated using the lowest quantities in the ingredient ranges.
- This dish can be made up to a day ahead and refrigerated tightly covered. When ready to bake, place covered in the oven and add 5 to 7 minutes to baking time.
- Be aware that the beets may bleed into the cream if prepared ahead, which affects appearance but not flavor.
- To minimize beet bleeding, coat beet slices lightly with cream and ensure the bottom layer of the dish has a thin coating of cream and Parmesan.
- The amount of cream may vary slightly depending on the surface area of your baking dish; adjust accordingly to ensure vegetables don’t dry out.
Nutrition
- Serving Size: 1/8 of casserole
- Calories: 280
- Sugar: 6g
- Sodium: 320mg
- Fat: 18g
- Saturated Fat: 11g
- Unsaturated Fat: 5g
- Trans Fat: 0g
- Carbohydrates: 22g
- Fiber: 4g
- Protein: 8g
- Cholesterol: 55mg
