Description
This Cheesy Root Vegetable Gratin is a comforting, flavorful dish featuring thinly sliced sweet potatoes, parsnips, and beets layered with creamy heavy cream, savory Parmesan, Gruyere cheese, fresh thyme, and garlic. Baked until tender and golden, it’s a perfect side dish for any meal, offering a rich combination of earthy root vegetables and cheesy goodness.
Ingredients
Scale
Vegetables
- 1-2 long sweet potatoes (about 2 inches thick), peeled
- 3-4 large parsnips, ends trimmed and peeled
- 3-5 small beets, peeled
Dairy & Cheese
- 14 tablespoons heavy cream, divided (whole milk can be used for a lighter dish)
- 4 ounces grated Parmesan, divided
- 1 ounce shredded Gruyere
- 1 tablespoon unsalted butter, softened (for greasing dish)
Herbs & Seasonings
- 1 tablespoon fresh minced thyme, divided (+ extra for garnish)
- 1 garlic clove, minced
- Salt and pepper to taste
Instructions
- Preheat Oven: Preheat your oven to 400°F (200°C). Grease a 3-quart baking dish with softened butter and set it aside for later layering.
- Slice Vegetables: Using a mandoline slicer, slice the sweet potatoes, parsnips, and beets into very thin rounds. Place each type of vegetable into its own separate bowl to prepare for seasoning.
- Prepare Vegetables: To the bowls with sweet potatoes and parsnips, add 4 tablespoons of heavy cream, and to the beet bowl add 2 tablespoons of heavy cream. Then, mix each bowl with ½ ounce of grated Parmesan, 1 teaspoon of minced thyme, salt, and pepper. Toss gently until all slices are evenly coated with the creamy mixture.
- Layer the Dish: Pour the remaining ¼ cup (4 tablespoons) of heavy cream into the greased baking dish, then sprinkle ½ ounce of Parmesan and the minced garlic over it. Begin layering the vegetables in rows—starting with sweet potato, then parsnip, then beet—repeating these rows until all the vegetable slices have been used.
- Season and Bake: Sprinkle the top layer of vegetables with the remaining Parmesan, and add salt and pepper to taste. Cover the baking dish tightly with foil and bake in the preheated oven for 30 minutes to allow the vegetables to soften.
- Add Gruyere: After 30 minutes of covered baking, remove the foil, sprinkle the shredded Gruyere cheese evenly over the top, and continue baking uncovered for another 18 to 20 minutes. Bake until the vegetables are fully tender and the top is golden brown and bubbly.
- Finish and Serve: Once baked, remove from the oven and garnish with extra fresh thyme. Serve the gratin warm as a delicious side dish.
Notes
- For a lighter version, substitute heavy cream with whole milk, but the gratin will be less rich and creamy.
- Using a mandoline slicer ensures evenly thin slices, which helps the vegetables cook uniformly.
- You can prepare the dish a few hours ahead and keep refrigerated; just add a few extra minutes to the baking time if baking from cold.
- If you don’t have Gruyere, you can substitute with another melting cheese like Fontina or a sharp white cheddar.
- Leftovers can be refrigerated for up to 3 days and reheated covered in the oven to retain moisture.
