2 c. cooked roast beef, cubed
2 tbsp. butter
2 tbsp. flour
1/2 c. cider vinegar
1 1/2 c. hot water
1 tsp. dry mustard
1 pkg. dry onion soup mix
1/2 c. brown sugar

Brown beef cubes in butter. Stir in flour. Combine remaining ingredients and add to meat mixture. Simmer 20 minutes. Serve over rice.