For the meatballs: Combine all ingredients except the olive oil in a large bowl. Mix well. Form about 16 meatballs and place on a platter. Heat the olive oil in a large skillet and fry meatballs over medium heat until browned. Repeat until all meatballs are browned. Place meatballs on new clean platter. Do not discard the oil.
For the Gravy: In the skillet, heat the reserved oil, add the onion and garlic and saute for approximately 2 minutes. Add the tomato paste and cook on medium heat for 3 minutes, stirring constantly. Fill the empty tomato paste can full of water, add to the skillet, and cook for 1 minute, stirring. Remove from heat and set aside.
In an 8-quart saucepan, add the ground tomatoes and cook on medium heat for 5 minutes. Fill the empty ground tomato can 3/4 full of water and add to the saucepan, along with the tomato paste mixture from the skillet and the reserved browned meatballs. Mix thoroughly but carefully with a wooden spoon so as to not break the meatballs. Add the salt, ground pepper, and parsley and cook on medium heat for 15 minutes, then cover and cook on low heat for 2 1/2 hours, stirring every 15 minutes to prevent sticking and burning on bottom of pan. Serve over al dente pasta and sprinkle with some grated Pecorino Romano cheese, along with crusty Italian bread and a good bottle of red wine.