Melt butter in a large skillet on medium heat and add the beef cubes. When all the sides are properly browned, remove to a bowl and set aside.
In the same pan add onions and caramelize for 2-3 minutes; set aside.
In the same pan add mushrooms, sherry cooking wine and Worcestershire sauce and sautee for 6-10 minutes or until the liquid is almost evaporated. Pour the flour and stir for one minute.
Add beef and onions and turn oven on low-medium heat. Slowly add sour cream and heat through while stirring thoroughly
Serve over your choice of side dish.
Recipe by CookingGlory at http://www.cookingglory.com/recipes/meal-ideas/soups-stews/beef-and-mushroom-stroganoff/