Make the Meatballs: In a large bowl, combine ground pork and ground beef with an egg, the breadcrumbs, parmesan or pecorino, garlic, fresh parsley and salt/pepper. Mix together, just until combined. You don’t want to overmix so that the texture of the meatballs stays light and fluffy.
Form the mixture into 1 inch meatballs, and arrange on a lined baking sheet. You can refrigerate until ready to use.
In a large pot over low-medium heat melt down the butter. Add pearl couscous and toast until lightly golden. Remove from the pot and set aside.
Add olive oil to the same pot over medium heat, along with the chopped onion, carrot, and celery. Sauté until everything begins to soften and get golden. Add the minced garlic and celery leaves to the pot and sauté until fragrant (about a minute).
Deglaze with ¼ cup of white wine, then add in your chicken stock, a parmesan rind, and some salt and black pepper to taste.
Bring to a bubble, then partially cover and let simmer for 10-15 minutes. Add the pearl couscous back into the broth and cook for another 5 minutes.
Next, gently add the meatballs directly to the pot, stirring lightly, and these will cook up in the next 3-4 minutes.
Lastly, add the chopped greens just before the soup is done cooking so that they soften.
Serve with some freshly grated parmesan or pecorino cheese and a drizzle of olive oil!