The main ingredient used to make custard is milk, often combined with eggs to create a creamy texture. Custard is a versatile dessert base, and the combination of milk and eggs can be sweet for desserts like flan or chocolate pudding or savory for dishes like quiche. The process involves heating milk while whisking in eggs and sugar (if sweet) until it thickens to a creamy consistency. This careful cooking method allows the flavors to blend, creating a rich, velvety result that can be enjoyed on its own or used in various desserts and pastries.