Sauces Bearnaise, Hollandaise and Mousseline

The methods used for these sauces are all very similar which is why I have included them under one heading. Although my sauce mousseline does not usually include butter, you may wish to add it to enrich the sauce.

Classically, the difference between a sauce hollandaise and a sauce béarnaise is that the latter uses vinegar and is flavoured with freshly chopped tarragon, whereas the former never includes tarragon and has been made in the past with everything from white wine reductions