• 2 cups water 
• grated rind of 1 lemon 
• 6 tablespoons all purpose flour 
• 3/4 cup sugar 
• 2 egg yolks 
• 1/4 cup butter 
• 3 tablespoons lemon juice 

Sprinkle lemon rind in water and bring to a boil in top of a double boiler, over direct heat. 
Mix flour and sugar together; add boiling water, a little at a time and return to double boiler. 
Cook over boiling water until thickened, stirring constantly. 
Cover and continue cooking 20 minutes longer, without stirring. 
Beat egg yolks slightly, add a little of the hot mixture to them; mix well and return to double boiler. 
Stir for 2 minutes. 
Remove from heat; add butter and lemon juice. 
Cool before using. 
  

Yield: enough for large layer cake.