1 tablespoon flour
1 teaspoon dry mustard
1/4 teaspoon salt
1/4 teaspoon pepper
1/2 cup water
1 tablespoon cider vinegar
1 tablespoon butter
1 tablespoon 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 to 2 minutes longer.
2. Remove from heat; stir in butter and mustard. Serve hot.
ABOUT 1/2 CUP