In a medium bowl combine the hamburger,parmesan cheese, parsley,1/2 Teaspoon salt, 1/2 teaspoon pepper,1/4 cup onion, egg and garlic. Mix to combine. Form into 1 inch balls. Place a saute pan on medium heat, fry the meatballs in the 2 Tablespoons of oil until done. Remove the meatballs from the pan, saute the onion,celery and carrots until softened.