Put the onion and garlic in a food processor and whizz to a fine paste. Add this to a bowl along with the mince, herbs and spices and a generous pinch of salt and pepper. Mix well with your hands (you can fry off a little bit to check the seasonings and flavours are to your liking) and shape into small sausage shapes. Chill for 20-30 minutes as this helps them to hold their shape when frying.
Heat about 2 tbsp olive oil in a large non-stick frying pan and add the meatballs. Fry on a fairly high heat, turning a few times until they are browned all over. Remove from the pan and set on some kitchen paper. Wipe the pan out with some kitchen paper and add the tinned tomatoes. Bring up to the boil, breaking the tomatoes up a little with a wooden spoon. Add some salt and pepper. Return the meatballs to the pan and simmer gently, uncovered, for 20 minutes, stirring occasionally. Add the fresh tomatoes and continue to cook for another 5-10 minutes until the sauce has thickened and reduced and the meatballs are cooked through.
Serve with rice, potatoes or pasta.