Lemon Sauce

½ cup sugar                                                       
4 tsp cornstarch
1 cup hot water                                                  
1 slightly beaten egg yolk
1 tsp grated lemon rind                                     
3-4 Tbs lemon juice
1 Tbs butter
 
Combine sugar and cornstarch in saucepan.  Gradually add hot water, blending until smooth.  Cook over high heat, stirring constantly, until thick.  Reduce head and continue cooking until clear, 5-7 minutes.  Remove from heat.  Blend in beaten egg yolk, to which a little of the hot mixture has been added.  Cook for 2 minutes.  Remove from heat.  Add lemon rind, lemon juice and butter.