1 tbsp. flour
1 tsp. dry mustard
1/8 tsp. salt
1/8 tsp. black pepper
1/2 c. water
1 tbsp. cider vinegar
1 tbsp. butter
1 tbsp. prepared mustard

1. Combine the flour, dry mustard, salt and pepper in a heavy saucepan. Gradually add the water and vinegar; cook, stirring until boiling; cook 1-2 minutes longer.

2. Remove from heat; stir in butter and prepared mustard. Serve hot.

My son will eat Brussels sprouts if he has this sauce over them.