Warm and bubbly. Yes please.
1 1/4 cup Heavy cream
1/4 cup Grated parmesan
1 Garlic clove, finely grated or chopped
1/2 tsp Chopped thyme leaves, plus more for topping
1/2 tsp Dry mustard
Kosher salt & fresh ground pepper, to taste
2 Medium sweet potatoes, peeled and sliced 1/8-inch thick
2 Large parsnips, peeled and sliced 1/8-inch thick
1 Small celery root, peeled and sliced into 1/8-inch thick half moon
1/2 cup `Grated gruyere
Preheat an oven to 375 degrees F. Butter a 2 1/2 to 3-quart gratin or casserole dish.
Meanwhile, bring the heavy cream, parmesan, garlic, thyme, mustard, 1/2 teaspoon salt, and a few grinds of pepper to a simmer in a small saucepan, stirring periodically; remove from heat.
Season each root vegetable separately with salt and pepper in a bowl, then tightly shingle each vegetable in rows in the casserole dish, creating alternating solid bands of color. Pour the heavy cream mixture over the shingled vegetables. Gently shake the dish so that the heavy cream gets in between the slices. Cover with foil. Bake until all the vegetables are tender, 45 minutes to 1 hour.
Increase the heat to 400 degrees F. Uncover and sprinkle with gruyere and some more thyme leaves. Bake until lightly golden on top, 20 to 25 minutes. Let rest 10 to 15 minutes before serving.
This root vegetable gratin features sweet potato, parsnip and celery for a filling main course or side dish. With the addition of parmesan inside and gruyere on top, it's a cheesy delight you'll come back to for seconds.
Prep Time: 20 minutes
Cook Time: 1 hour 10 minutes