One of several French "mother sauces", Hollandaise is the base for several other sauces, including bearnaise sauce and paloise sauce. Hollandaise sauces are typically served lukewarm, reheating can cause them to curdle. A recipe for Hollandaise is below:

Ingredients

1 1/2 sticks unsalted butter
4 eggs yolks
1 tablespoon cold water
1/4 teaspoon salt
Dash of white pepper
1 teaspoon lemon juice

Instructions

Melt butter in small saucepan. Remove from heat and skim off foam. Remove impurities from butter (One method is to: pour melted butter into plastic bottle with nozzle and stand the bottle upside down into a cup, the impurities will settle in the nozzle).

Remove the thick white piece that sometimes adheres to the egg yolks, put yolks and water into heavy pan. Heat on low on rangetop and beat continously with a wire whisk until a thick custard forms (if the mixture is cooking too fast, remove from heat and set pan in cold water).

When the mixture is thick, gradually add the butter into custard drop by drop, beating constantly. Leave white residue in the bottom of the butter pan. Once butter is added, season with salt, pepper and lemon juice.

Pour sauce into serving dish, keep dish in warm water at the same temperature as the sauce.