What is White sauce?

The most basic white sauce, from which numerous other sauces stem. White sauce is made with a roux of butter and flour mixed with milk and cooked over a gentle heat until smooth and slightly thick. Béchamel is the king of white sauces. It differs slightly from the basic white sauce in that the milk is flavoured first with onion and seasoning (often nutmeg).

You can add a variety of ingredients to a basic white sauce to transform it into something more flavoursome, such as chopped parsley, grated cheese, white wine, cooked chopped mushrooms, cooked onions, and so on.