Mix the mince, finely chopped onion (if using), parmesan, parsley, ham, salt, pepper and egg together in a bowl. If the mixture is too "wet" and doesn't stick together, add some breadcrumbs: 2 Tbsp at a time until it becomes more firm.

If you have time, place the mixture in the fridge for 30 minutes.  This step is not strictly necessary, but it helps the balls stay together while they are being browned.

Make balls about the size of a walnut with your hands.

Heat olive oil in a frying pan (with high sides if possible) with a large sprig of rosemary and a whole clove of garlic.

Brown the meatballs.  Do not crowd them together.  If the pan is too small, put them in a few at a time. Gently turn them until they are browned on all sides.

Add the red wine and let it boil off.

If you do not have a pan with high sides, transfer the meatballs to a larger pot.  Add the tomato passata, the boullion cube and the peas. Top up with a little water if the sauce is too thick.  Add salt to taste.

Simmer gently for 15 -20 minutes, stirring occasionally.

If the sauce is too runny, turn the heat up briefly to let the sauce thicken.

These are great to freeze!  Just make sure the sauce is quite runny and covers the meatballs entirely before putting them in the freezer.