Mustard Sauce - Barbara Seng

2 tbsp flour                                          
2 tbsp butter
½ tsp salt                                              
⅛ tsp pepper
1 tsp sugar                                            
1½ cups milk
2 tsp vinegar                                        
1 tbsp prepared mustard

Melt butter and blend in flour.  Stir in salt, pepper and sugar.  Gradually add milk and cook, stirring until thickened.  Add vinegar and mustard.