Put 1 tbsp rapeseed oil in a frying pan over a medium heat. Add the onion and fry for 10 mins or until soft and translucent. Add the garlic and cook for 1 min. Leave to cool.

Mix the cooled onions, pork mince, egg yolk, a good grating of nutmeg and the breadcrumbs in a bowl with your hands until well combined. Form into 12 balls and chill for 15 mins.

Heat the remaining oil in a frying pan and fry the meatballs for 5 mins over a medium heat, turning often until golden. Pour over the stock and bubble for 8-10 mins or until it has reduced a little. Stir through the mustard and yogurt.

Steam the greens for 5 mins or until tender. Serve the meatballs with the greens and a dollop of the sauce.