Baked Rigatoni with Fontina and Celery Root Puree

Name: Baked Rigatoni with Fontina and Celery Root Puree
Ingredients: • 8 oz dry Rigatoni pasta; • 4 cups whole milk, divided; • 2 cups water; • coarse salt to taste; • 1 large celery root (about 1 1/2 pounds total), peeled, cut into 2-inch cubes; • 1 small onion or 2 shallots, diced; • 6 tablespoons butter, cut into 6 pieces; • 2 tablespoons flour; • About 1/4 teaspoon freshly grated nutmeg; • Ground white pepper; • 1 teaspoon Herb de Provence; • 1 1/2 cups Italian Fontina Cheese, shredded on the large side of grater; • 2 tablespoons freshly grated Parmesan cheese; • 2 tablespoons Panko bread crumbs