1Cut meat into strips about 2" long and the width of a pencil. Pat dry and salt and pepper meat to your liking. Set aside.
If using whole creminis, slice or quarter them.
Melt 3 Tbl. butter in heavy skillet, add onions and saute til just soft. Add mushrooms and cook 3-5 minutes longer til mushrooms are soft and onions are browning.
Remove from pan, set aside.
Add remaining Tbl. of butter to pan and turn up the heat. Toss in steak and garlic making sure the pieces of steak are all laying flat, sear quickly on both sides leaving RARE. Remove meat and set aside, (back into it's original bowl is just fine.) Blend flour into butter and juices in pan. Cook and stir for 1-2 minutes. Do not brown. Gradually add beef bouillon, stirring constantly, until smooth and thickened. Add tomato paste and wine and blend thoroughly. Add steak, garlic, mushrooms and onions back into pan, heat through on low heat for rare-medium rare stirring gently. (Cook longer for medium to well. Up to 20 minutes.) Blend in sour cream 5 minutes before serving over LOW heat so it doesn't to curdle. Add salt and pepper to taste. Serve over cooked egg noodles. *Can garnish with fresh chopped parsley if desired.