2 tbsp. butter
1 sm. onion, finely chopped
2 chicken bouillon cube
2 tbsp. water
1 (2 1/2 oz.) jar sliced mushrooms, drained
Reserved soup mixture from chicken filling

Melt butter in large skillet and saute onion until tender. Add bouillon cube, water and mushrooms. Cook, stirring often, until cube dissolves. Stir reserved soup mixture into skillet.