preparing the meat mixture: Add the kaiser roll, parmesan, parsley and ¼ raw onion to the food processor bowl. Pulse until finely grind (if you don‘t have a food processor - you can chop it very finely).
Dice the remaining ¾ onion, finely chop the garlic. Heat 1 tablespoon of oil on a very large frying pan, add the onion and cook for about 5 minutes, until translucent, add the garlic, cook for 30 seconds. Remove from the pan and set aside to cool.
Add the drained ricotta, egg, lightly cooled onion with garlic, ground fennel seeds (you can do it using pestle and mortar or a coffee grinder), oregano, salt and pepper to the food processor bowl. Pulse until combined (or mix with your hands).
Add the meat, use your hands to thoroughly mix the ricotta mixture into the ground meat just until combined (but don‘t overwork the meat so that the meatballs stay tender).
Add the additional breadcrumbs if necessary (it will depend on how big and dry your bread roll was). Add it when the meatballs don‘t hold their shape.
If you plan to roast the meatballs – preheat the oven to 240°C / 475°F / Gas Mark 9, no fan, OR 220°C / 450°F with fan (or if you have a convection oven).
shaping the meatballs: Pour a small amount of oil into a small bowl. Coat your hands well and shape the meatballs, a little bigger than walnuts. I scooped the meat mixture with an ice cream scoop, measured the balls (each ball weight 50g) and shaped the meatballs with oil-coated hands (you should have 23 meatballs). Place the balls on two plates. They should keep their shape. Alternatively, you can pop the meat mixture in the fridge for an hour or two to make it easier to shape.
Now you need to brown the meatballs (either on a pan or in the oven) and simmer them in tomato sauce