Baked Mashed Potatoes with Parmesan Cheese and Bread Crumbs

INGREDIENTS

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