Saute onions in olive oil or beef fat over hight heat till they are browned but not soft. Add garlic near end. Set aside. Cut bread slices into cubes. Meanwhile whisk together eggs, worcestershire sauce, mustard, tomato paste, horseradish, Italian Seasoning, celery seed, salt and pepper. Sprinkle gelatin over surface and let sit 5 minutes. Whisk well. Set aside. Put meat, parmesan, and parsley in large bowl. Add onions, egg mixture, bread, breadcrumbs. Blend gently but well with hands. Form 1-1/2 to 2 inch balls. In large skillet using medium-high heat, fry in olive oil until well browned on all sides. The meatballs will be almost cooked through. They will finish cooking when added to sauce to simmer a while longer. If not adding to sauce, lower heat a little and cook longer. Test a meatball to be sure. John is willing to test thoroughly to be sure. Note: This recipe using 9.25 pounds of meet made 95 meatballs. Seems to consistently make 10 meatballs per pound of meat.