Baked Mashed Potatoes Recipe

• 1 tablespoon butter
• 4 pounds russet potatoes, peeled, cut into 1-inch pieces
• 1 cup whole milk
• 1/2 cup (1 stick) butter, melted
• 1 1/2 cups grated mozzarella
• 1 cup freshly grated Parmesan
• Salt and freshly ground black pepper
• 2 tablespoons plain dry bread crumbs

Directions