Description
This Cheesy Root Vegetable Gratin is a perfect festive side dish for Thanksgiving dinner, featuring layers of tender sweet potatoes, parsnips, and beets baked in a creamy Parmesan sauce and topped with melted Gruyere cheese. The gratin is seasoned with fresh thyme and garlic, creating a flavorful, comforting dish that highlights the natural sweetness of root vegetables.
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 and Cheese
- 1 tablespoon unsalted butter, softened
- 14 tablespoons heavy cream, divided (whole milk can be substituted)
- 4 ounces grated Parmesan cheese, divided
- 1 ounce shredded Gruyere cheese
Herbs and Seasoning
- 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 your oven to 400˚F (200˚C). Grease a 3-quart (3 liter) baking dish with the softened butter to prevent sticking.
- Slice Vegetables: Using a mandoline or a sharp knife, slice the sweet potatoes, parsnips, and beets into very thin rounds. Separate each vegetable into its own bowl to season individually.
- Season Vegetables: Pour 4 tablespoons of heavy cream over the sweet potatoes and parsnips each. For the beets, pour 2 tablespoons of cream. To each bowl, add ½ ounce of grated Parmesan and 1 teaspoon of minced thyme. Generously season all vegetables with salt and pepper, then toss gently to coat all slices evenly.
- Prepare Baking Dish Base: Pour the remaining 1/4 cup (4 tablespoons) of cream into the bottom of the greased baking dish. Sprinkle ½ ounce of Parmesan cheese and the minced garlic evenly over the cream to form a flavorful base.
- Assemble Gratin: Starting with sweet potatoes, stand a stack of slices upright on a bias along the top edge of the baking dish. Follow with a row of parsnips, then a row of beets. Repeat the pattern with the remaining vegetables to create six distinct rows of layered root vegetables.
- Season and Cover: Sprinkle the top of the layered vegetables with salt, pepper, and the remaining Parmesan cheese. Cover the baking dish tightly with aluminum foil.
- Bake Covered: Place the covered gratin in the preheated oven and bake for 30 minutes, or until the vegetables are tender when pierced with a fork.
- Uncover and Add Cheese: Remove the foil, sprinkle the shredded Gruyere cheese evenly over the top, and return the dish to the oven uncovered.
- Finish Baking: Continue baking 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, sprinkle with fresh thyme leaves for garnish, and serve warm as a delicious side dish.
Notes
- Makes one 3-quart (approximately 3-liter) casserole dish serving 8 people.
- Nutrition facts are calculated based on the lower estimates of vegetables used (e.g., 1 sweet potato, 3 parsnips, 3 beets).
- This gratin can be prepared up to a day in advance and refrigerated, covered tightly with foil. When ready to bake, add an extra 5-7 minutes of baking time while covered.
- Beets may bleed their color into the cream if prepared ahead, which affects appearance but not flavor.
- To minimize beet bleeding, coat the beet slices lightly with cream, and ensure the bottom of the baking dish is lightly coated with cream and Parmesan.
- The amount of cream used can vary slightly based on the size and surface area of your baking dish, so adjust as needed to keep vegetables moist but not soaked.
Nutrition
- Serving Size: 1 slice (about 1/8 of the casserole)
- Calories: 280 kcal
- Sugar: 5 g
- Sodium: 210 mg
- Fat: 18 g
- Saturated Fat: 10 g
- Unsaturated Fat: 6 g
- Trans Fat: 0 g
- Carbohydrates: 22 g
- Fiber: 4 g
- Protein: 9 g
- Cholesterol: 55 mg
