- 2 1/2 pounds of sweet potatoes and parsnips, peeled and thinly sliced
- 1 1/2 cups of heavy cream
- 4 garlic cloves, minced
- 2 tablespoons unsalted butter, plus more for greasing casserole dish
- 3–4 sprigs of fresh thyme
- Juice from 1/2 a lemon
- Freshly ground pepper
- 1 cup gruyère cheese, grated
- Preheat oven to 400 degrees.
- Put heavy cream in a small saucepan. Add garlic, butter, 1 teaspoon salt, and black pepper. Turn heat to medium-low. As soon as the cream comes to a boil, stir, turn off the heat and top the saucepan with a lid. Let the cream infuse for 15 minutes. Strain or scoop out garlic leaving just the liquid behind.
- While the cream is infusing, prepare an oven-safe 9″ x 12″ casserole dish with butter. Arrange sliced sweet potatoes and parsnips into the dish, then squeeze lemon juice over the vegetables.
- Pour over cream mixture, cover with tin foil, and bake for 45-55 minutes or until vegetables are fork tender. Remove foil and sprinkle shredded gruyère over top. Bake, uncovered, for an extra 15 minutes until browned and bubbly.