Hollandaise sauce is one of the classic butter sauces and is traditionally served with asparagus. But the sauce with its fine acidity doesn't just go perfectly with asparagus. It is also an ideal accompaniment to other vegetables, but also to fish and meat.

A hollandaise sauce lasts an entire evening if it is not kept too hot. The secret of making the sauce is the right temperature during preparation. The lecithin contained in the egg yolk should serve as an emulsifier. However, the egg must not get too hot, otherwise it will curdle.

The perfect temperature for preparation is . . .