Beef Stroganoff

2 lbs stew meat
1 onion minced
4 Tbsp butter
2 Tbsp ketchup
4 Tbsp Worchestershire sauce
4 Tbsp beef base
4 cups sliced mushrooms
24 oz sour cream

In a large saucepan melt butter and sautee onions. Sear meat. Once browned add mushrooms, Worchestershire sauce, ketchup and beef base. Cover in water, turn heat to low and let simmer uncovered until meat is tender. Temper sour cream into meat mixture. Serve over egg noodles or rice.