Au Blanc is a French term for a cooking method that results in “white” food.
When used in reference to meat, the meat is poached or simmered in either a white stock or white sauce, so that the meat won’t colour. The meat might also be served with a white sauce.
When referring to vegetables such as cauliflower, salsify, etc, the term usually infers that the vegetable was simmered in water mixed with a pinch or two of flour, salt and lemon juice. Such a mixture, often referred to as a “court bouillon”, will make those vegetables turn out pure white.
Note: a “court bouillon” can be constituted of many things other than the ingredients referred to here, when the purpose is not to render something white.
Quantity for white “court bouillon” for vegetables. Per 1 litre of water, salt to taste, plus 20 grams of flavour and juice from 1 lemon. Mix, bring to a boil, and add the vegetables to start cooking them.