Hollandaise sauce

Ingredients:
200 grams of butter
3 egg yolks
1/2 lemon
Salt pepper

Preparation :
Start by squeezing the lemon, then cut the butter into cubes.
Beat the egg yolks until the mixture becomes foamy
Add the lemon, salt and pepper. Mix.
Place the bowl in a saucepan in a bain-marie and whisk until you obtain a creamy sauce.
Add the melted butter while continuing to mix.
The mixture should thicken.