Saute onion in butter in a skillet until tender. Stir in wine; simmer 2 minutes. Add cream cheese, sour cream, mayonnaise and beef; mix well. Spoon mixture into an 8-in. square baking dish; sprinkle with pecans. Bake at 350 deg. for 15 to 20 minutes. Serve with assorted crackers. Yield: 4 cups