In a bowl, knead the minced meat with the Grana Padano, breadcrumbs, pressed garlic cloves, eggs, salt and pepper to form an even dough. Shape the minced meat dough into meatballs that will roughly fit in one hand. (There will be about 12 meatballs).
Fry the meatballs lightly brown in plenty of oil and then set aside on a plate.
Cut the onion into cubes (it can be coarser as it overcooks) and slice the remaining two cloves of garlic. Sauté both in a large saucepan with olive oil and then add the tomatoes. Put a shot of water in each pack of the tomato strains, shake and add the tomato water to the pot. It is important that there are no more than 1 1/2 glasses of water in the tomato sauce, otherwise it will become too runny. Add salt, pepper and two tablespoons of sugar and bring to the boil.
As soon as it comes to a boil, turn the stove back to a low setting so that it just simmered. Put the meatballs in the tomato sauce and let everything simmer with the lid closed for at least 2 hours. Half an hour before the end of the cooking time, add another shot of olive oil and season again with salt and pepper to taste.
Pasta goes well with it, especially rigatoni or penne.