Mornay sauce is simply a béchamel sauce with grated cheese mixed in. Traditionally, Gruyère is used, but there’s nothing stopping you from adding cheddar, Emmental, Swiss or any other firm cheese. This variation of the classic sauce brings creaminess and flavour to any dish it accompanies. It can be used as a base for macaroni and cheese, or also to top Florentine eggs and cooked cauliflower.