Not only are breakfast casseroles warming on a cold morning, but they are also the ultimate crowd pleasers. Just throw all of your favorite ingredients into a casserole dish and bake. You can customize the recipe based on the meats and vegetables that you have on hand that morning. Even better, use of any leftovers from the night before, such as sautéed vegetables or sliced bread, in an eggy casserole the next day. Food & Wine has plenty of flavoring ideas, like this Christmas-morning casserole with bits of pepperoni, mushrooms and gooey cheese.