1/2 cup butter
 2 T. grated lemon rind
 1/2 cup lemon juice
 1 1/2 cups sugar
 3 whole eggs
 3 egg yolks  
 In top of a double boiler, melt the butter.  Stir in lemon rind, juice 
 and sugar.  Beat the eggs and yolks together until thick; blend into 
 lemon mixture.  Cook, stirring constantly, over hot water until mixture 
 is very thick.  Chill before using.
 Source: 1957 Woman’s Day Collector’s Cookbook