Ingredient:

• 2 Yukon Gold potatoes, scrubbed and sliced 1/8-inch thick with peel
• 1 turnip, peeled and sliced 1/8-inch thick
• 1 rutabaga, peeled and sliced 1/8-inch thick
• 1 small celery root, peeled and sliced 1/8-inch thick
• 1 parsnip, peeled and sliced 1/8-inch thick
• salt, to taste
• 3 cloves garlic, minced
• 2 tablespoons butter
• 1 ¼ cups chicken broth
• 1 cup heavy cream
• 1 tablespoon chopped fresh thyme
• 1 pinch ground nutmeg
• 1 pinch cayenne pepper
• 2 teaspoons olive oil
• ¼ cup finely grated Parmigiano-Reggiano cheese, divided