In a medium sized pan, heat the olive oil and fry the finely diced onion until soft, fragrant and transparent, then transfer to a dish to cool to room temperature.
In a large mixing bowl, combine the ground pork and ground beef, salt, fine black pepper, garlic powder, whisked egg, torn pieces of bread, grated cheese, and finely chopped flat leaf parsley or celery leaves, then add the onion and combine well.
Scoop out 1½ teaspoons of the meatball mixture and weigh it on digital kitchen scales – you’ll want 18-20 g per meatball – then roll the mixture between two hands to shape into small meatball, place on a baking tray, and repeat until you’ve finished the mixture. It should make around 40 meatballs.
Heat the olive oil in a round flat-bottomed wok (or deep medium-sized fry pan) over high heat, then fry the meatballs in batches, turning every minute, for four minutes, until they’re all done, then set aside.
In a Dutch oven or soup pot, over medium-high, heat the olive oil, then fry the onion until soft, add the finely chopped garlic cloves and fry until fragrant, then add the diced carrot and celery and fry for a few minutes more. Turn down the heat if too hot, and add a little water if the garlic starts to brown.
Add the stock or water and bouillon, salt and pepper, and increase the heat to bring to a boil, then reduce heat to low to simmer. Add the meatballs and spinach or wild greens, and simmer until the greens are soft.
Just before you’re ready to serve, add the cooked pasta and half the grated cheese. Ladle the soup into bowls and sprinkle with more grated cheese and salt and cracked black pepper to taste and serve with slices of sourdough.