5 egg yolks
1 cup sugar
1/8 teaspoon cream of tartar
1/3 cup water
1 cup softened butter
Beat egg yolks until thick and fluffy in a mixing bowl. Set aside. Combine sugar, cream of tartar, and water in a saucepan. Stir over low heat ntil sugar is completely dissolved. Bring to a boil and boil without stirring until candy thermometer reads 240 degrees (soft ball in cold water). Add syrup to the egg yolks in a thin stream, stirring constantly. Beat until cool. The mixture will become thick and light. Cool completely. Beat in the butter. Flavor as desired.
Makes about 2 cups