Definition: béarnaise

It is mainly served with grilled meat and fish. It is a hot emulsified sauce made with egg yolks heated over a reduction of vinegar/white wine to which butter is added. If reduced tomato purée is added, it becomes a Choron sauce. It seems that this sauce is not originally from Béarn at all, but was named in memory of King Henry IV, known as the "Grand Béarnais".