Hollandaisesaus

Hollandaise sauce is an emulsion of butter, egg and vinegar or wine -- essentially a warm mayonnaise. Many people think it is French, but a recipe for Hollandaise sauce appears in a Dutch cookbook by Carel Baten, dating from 1593. And, if you're familiar with historical Dutch recipes you'll know that egg custards and combinations of butter and vinegar were incredibly commonplace in early Dutch cooking.

The sauce is traditionally coupled with asparagus, but it is also great with seafood and steaks.