1/3 c. red wine vinegar
1/3 c. salad oil
1 sm. onion, sliced, separated
1 tsp. salt
2 tsp. parsley
1 tsp. prepared mustard
1 tbsp. brown sugar
1 lb. mushrooms, cleaned & sliced

Bring above ingredients (except mushrooms) to a boil. Add mushrooms and simmer for 15 minutes.