Saute bacon in skillet over medium-high heat until slightly crisp, 5 minutes. Remove to paper toweling. Reduce heat to low. Add onion to skillet; saute 10 minutes or until lightly golden and softened.
Place cream cheese, Gouda, onion, mustard, vinegar and pepper in processor. Pulse to blend. Turn into bowl. Stir in bacon and nuts. Cover; refrigerate 24 hours or up to 1 week.