The main ingredient in a quiche is eggs, which create the custard base. A classic quiche consists of a pie crust filled with a mixture of eggs, cream or milk, cheese, and a variety of other ingredients such as vegetables, meats, or seafood. Quiche can be served hot or cold and is often enjoyed for breakfast, brunch, or lunch. Quiche Lorraine, for example, includes bacon or lardons, while other variations may include spinach, mushrooms, or tomatoes. This versatility in ingredients and flavors makes quiche a popular dish in many cuisines.