From Sunsational.

Mustard Sauce

3/4 cup sugar
4 Tablespoons flour
1/8 teaspoon salt
8 Tablespoons margarine
3/4 cup prepared mustard
1/4 cup water
1/4 cup horseradish
3/4 cup vinegar
3/4 cup Miracle Whip

Mix sugar, flour, salt, margarine, mustard, water and horseradish in pan. Heat and stir until thick. Then add vinegar and cook 5 minutes or more. Let cool, add Miracle Whip. Keeps in the refirgerator for a long time. This is excellent for ham.