Dredge Meat In Flour. In A Skillet, Melt 1/4 Cup Butter Over Medium Heat; Saute Onions Until Tender. Remove From Pan; Set Aside. Melt Remaining Butter And Brown Meat On All Sides. Add Broth, Basil, Salt And Pepper, Mushrooms, Worcestershire Sauce And Onions. Cook Until Mixture Thickens, About 5 Minutes. Just Before Serving, Stir In Sour Cream. Heat Through, But Do Not Boil. Serve Immediately Over Rice Or Noodles.