Combine meats, onion, parsley, salt, and pepper. Add butter and oil to pan and begin rolling small, bite-size balls, adding balls to pan as you roll them. Cook balls 10 to 12 minutes, shaking pan occasionally to brown equally on all sides. Deglaze pan with wine and allow wine to reduce by half, 1 or 2 minutes. Remove pan from heat and squeeze the juice of 1/2 lemon over the meatballs.