Description
This Cheesy Root Vegetable Gratin is a comforting and flavorful dish featuring layers of thinly sliced russet potatoes, sweet potatoes, parsnip, and turnip baked in a rich creamy mixture and topped with Gruyere and Parmesan cheeses. Perfect as a hearty side dish, it combines the natural sweetness of root vegetables with savory melted cheese and fresh thyme, delivering a warm and satisfying meal that’s ideal for cozy family dinners.
Ingredients
Scale
Vegetables
- 2 large russet potatoes, peeled and thinly sliced
- 2 medium sweet potatoes, peeled and thinly sliced
- 1 large parsnip, peeled and thinly sliced
- 1 large turnip, peeled and thinly sliced
Cream Mixture
- 1 1/2 cups heavy cream
- 1 cup milk
- 2 cloves garlic, minced
- 1 teaspoon salt
- 1/2 teaspoon black pepper
- 1/4 teaspoon nutmeg
Cheese and Garnish
- 2 cups shredded Gruyere cheese
- 1 cup grated Parmesan cheese
- 2 tablespoons unsalted butter
- 2 tablespoons chopped fresh thyme
Instructions
- Preheat and prepare baking dish: Preheat your oven to 375°F (190°C). Butter a 9×13-inch baking dish thoroughly to prevent sticking and add richness.
- Make cream mixture: In a large saucepan, combine heavy cream, milk, minced garlic, salt, black pepper, and nutmeg. Bring the mixture to a gentle simmer over medium heat, stirring occasionally to blend the flavors. Once it starts simmering lightly, remove from heat to prevent boiling.
- Layer first half of vegetables: Arrange half of the sliced vegetables—russet potatoes, sweet potatoes, parsnip, and turnip—in the prepared baking dish, overlapping the slices slightly for an even layer.
- Add cream and cheese layer: Pour half of the warm cream mixture evenly over the first layer of vegetables. Then, sprinkle half of the shredded Gruyere and grated Parmesan cheeses over the top to create a flavorful cheesy layer.
- Layer second half of vegetables: Place the remaining sliced vegetables on top of the cheese, again overlapping slightly for consistent coverage.
- Finish with remaining cream and cheese: Pour the rest of the cream mixture over the vegetables, then sprinkle on the remaining Gruyere and Parmesan cheeses to top off the dish.
- Add butter and thyme: Dot the surface of the gratin with small pieces of unsalted butter. Sprinkle the chopped fresh thyme evenly over the top for an aromatic finish.
- Bake covered: Cover the baking dish tightly with aluminum foil and bake in the preheated oven for 60 minutes. This step allows the vegetables to cook through gently in the creamy environment.
- Bake uncovered until golden: Remove the foil and continue baking for an additional 15-20 minutes. This will give the gratin a golden brown, bubbly top and ensure the vegetables are tender when pierced with a fork.
- Rest before serving: Allow the gratin to rest for 10-15 minutes after removing it from the oven. This resting period lets the flavors meld and the cheese set properly, making it easier to serve and enjoy.
Notes
- Use a mandoline slicer for evenly thin slices to ensure even cooking.
- To make ahead, assemble the dish up to Step 6, refrigerate covered overnight, then bake as directed, adding extra baking time if baking from cold.
- Substitute heavy cream with half-and-half for a lighter version, though the texture will be less rich.
- Fresh thyme can be replaced with rosemary or sage for a different herbal note.
- Letting the gratin rest is crucial for the cheese to set and the dish to firm up for clean slices.
