Melt 2 tablespoons of butter in large non stick frypan. Saute mushrooms until tender and any liquid has evaporated; remove from pan; set aside. Melt remaining 2 tablespoons butter in same frypan. Saute chicken breasts on both sides until golden brown and cooked through; remove from pan; set aside. Add onions to pan; saute until tender. Add water, wine and boulillon mix to pan. Bring to boil. Cook and stir until mixture is reduced by half. Add cream to pan. Cook and stir until slightly thickened. Add salt and pepper to taste. Return mushrooms and chicken to sauce in pan. Reheat to serving temperature. Makes 4 to 6 servings.