1 lb. boneless sirloin steak, cut into 4 pieces and lightly pounded
1 medium onion, thinly sliced
1 package (10 oz.) white button mushrooms
1 tub Knorr® Homestyle Stock - Beef
1 1/4 cups water
1/4 cup dry red wine
1/2 tsp. fresh thyme or 1/8 tsp. dried thyme leaves
Melt 1 Tbsp. margarine in 12-in. skillet and cook steak over medium-high heat, turning once, until desired doneness, about 6 minutes. Remove steak from skillet and keep warm.
Melt remaining margarine in same skillet over medium heat and cook onion and mushrooms, stirring occasionally, until vegetables are golden, about 10 minutes. Stir in Knorr® Homestyle Stock - Beef until Stock is melted. Stir in water, wine and thyme and bring to a boil over high heat. Reduce heat to low and simmer until slightly thickened, about 2 minutes.
Serve onion and mushroom sauce over steak and, if desire, with hot mashed potatoes.