To make the meatballs:
To make the stock, brown the meats and the onions in olive oil and season with salt and pepper (add the cloves into the onion so you don’t lose them).
In about ⅘ minutes the meat should be well golden on both sides, now you can add cold water enough to submerge everything and add the rest of the ingredients for the stock making sure everything is well rinsed.
Simmer on low heat for about 90 minutes to extract all flavor.
Now filter the stock through a sieve and keep on the side. Discard the onions, garlic, celery, herbs, and cheese rind.
Pick the meat from the bones and mix in a blender along with the cooked carrots, potato, the egg yolks, and a pinch of salt.
Once the mixture is done, stir in the grated cheese, chopped parsley, and enough breadcrumbs to make the mixture pliable so that you could shape tiny meatballs out of it.
Shape them into mini meatballs of about 1 to 2 cm in size.
Bring the stock to a simmer and boil the meatballs in it in small batches.
Cook for 2 minutes in the simmering stock and keep on the side.
Use the flavorful stock to cook the pastina in and serve it along with your preferred amount of mini meatballs. Garnish with more grated Grana Padano and enjoy.
