Serve with blanched asparagus or green beans, on egg dishes, and with poultry, fish or seafood dishes.
Season the egg yolks and beat well.
Place in a glass bowl and blend with a stick blender.
Heat the lemon juice and vinegar in a heavy-based saucepan.
Bring to the boil and remove from heat.
With blender running, add the hot liquid to the eggs and blend until well mixed.
Melt the butter until foaming and add to eggs with blender running.
Thin hollandaise sauce down by beating in a little warm water.