Preheat the oven to gas mark 4 (180°C). Prepare a baking tray with a baking sheet.
Mash the butter beans with a folk. Fry the onion and the garlic, add in the mashed butter beans. Mix well.
Add the rest of the ingredients to the bean mixture and mix well with your hand.
Form meatball shape with your hand and make 12 of them (if you make smaller size meatball it will make about 15). Put them on the baking tray.
Bake them for about 10 minutes, turn over and bake them for another 10 minutes. Bake longer if you want to make them crispier.