- 4 cups heavy whipping cream
- 2 cups low-salt chicken broth
- 6 large fresh thyme sprigs
- 4 large fresh sage sprigs
- 2 large fresh rosemary sprigs
- 2 large garlic cloves, pressed
- 1 tablespoon coarse kosher salt
- 1 teaspoon ground black pepper
- 1/4 teaspoon ground nutmeg
- 1/4 teaspoon cayenne pepper
- 3 1/2 pounds russet potatoes
- 1 cup freshly grated Parmesan cheese
Position rack in top third of oven and preheat to 350°F. Bring first 11 ingredients to boil in large saucepan. Reduce heat and simmer until mixture is reduced to 33/4 cups, about 35 minutes. Strain cream mixture into large bowl.
Peel potatoes; cut into 1/8-inch-thick rounds, adding immediately to cream mixture to prevent discoloration. Peel turnips; cut into 1/8-inch-thick rounds. Add to potato mixture; stir to coat.
Pour vegetable mixture into 15x10x2-inch glass baking dish and press to even layer. Cover dish with foil. Bake 1 hour. Uncover; sprinkle with cheese. Bake until top is golden brown, potatoes are tender, and most of cream mixture is absorbed, about 25 minutes longer.