NOTE: Keep heat low ~ Stir briskly all the time. If sauce separates add 1 tsp. water & heat while stirring it in slow. In small saucepan stir in egg yolks & lemon juice with wooden spoon. Add half the butter. Stir over very low heat until butter is melted. Add rest of butter. Continue stirring until butter is melted & sauce thickened. Be sure butter melts slowly as this gives eggs time to cook & thicken the sauce without curdling. Any sauce left over will keep in frig. To serve, stir a little hot water in.