Try the make-ahead option. A mix of root vegetables, such as carrots, parsnips, and yellow potatoes, is especially yummy.

Prep: 25 minutes   Cook: 20 minutes    Bake: 15 minutes   Oven: 400°

6 lb. assorted root vegetables, such as carrots, parsnips, turnips, rutabagas, and/or red or yellow potatoes
6 cloves garlic, peeled
1 Tbsp. kosher salt, divided
1/2 cup milk, half-and-half, or light cream
2 Tbsp. olive oil
2 Tbsp. butter
1/2–1 tsp. freshly ground black pepper
1/3 cup snipped fresh Italian (flat-leaf) parsley
1 1/2 cups shredded Parmigiano-Reggiano cheese (6 oz.)

1. Peel root vegetables and cut in 2- to 3-inch pieces. Place the root vegetables, garlic, and 1 1/2 teaspoons of the salt in a 4- to 6-quart Dutch oven and fill with enough cold water to cover. Bring to boiling. Reduce heat and simmer, covered, for 20 minutes or until very tender. Meanwhile, in a small saucepan heat milk, olive oil, and butter until warm and butter is melted.

2. Drain vegetables in a colander. Return to Dutch oven. Mash with potato masher; stir in milk mixture, 1 1/2 teaspoons salt, and pepper. Stir in Italian parsley and 1 cup of cheese. Place vegetable mixture in a 3-quart gratin dish (preferably broiler-safe—see broiling step below); spread evenly. Top with remaining 1/2 cup cheese.

3. Bake, uncovered, in a 400° oven for 15 minutes or until cheese is melted and mixture is heated through. If desired, preheat broiler; place dish 4 to 5 inches from the heat and broil for about 2 minutes or until top is browned (dish must be broiler-safe). Makes 12 servings.

TO MAKE AHEAD: Spread mashed vegetables in the baking dish and cool slightly. Top with remaining cheese, cover, and chill for up to 24 hours. Uncover and bake in a 400° oven for 30 minutes or until heated through.