1/3 c. red wine vinegar
1/3 c. salad oil
3 tbsp. brown sugar
1 tbsp. prepared mustard
1 tsp. salt
1 tbsp. parsley flakes
1 sm. onion, sliced thin

Mix all ingredients together. Bring all to a rolling boil. Add 3 or 4 jars drained button mushrooms. Simmer 5 or 8 minutes. Chill completely in refrigerator before serving.