Preheat oven to 375 degrees F with the rack in the middle. Combine the ground meat, bread crumbs, 1 egg, 1/4 cup of each cheese, parsley, salt and pepper in a bowl. Mix thoroughly, then form the mixture into 3/4-inch to 1 1/2-inch balls. You should have 20 to 30 meatballs, depending on how large you form them. Place them on a baking sheet and bake about 8 minutes. Remove & set aside.

In a 4- to 6-quart soup pot, heat the remaining 1 tablespoon oil over medium-high heat. Add the onion, garlic and carrots. Sauté until the onions are tender and the garlic is soft, but not browned, about 5 minutes. Add the stock and bring to a boil. Add the spinach, reduce the heat to low, cover, and simmer for 10 minutes. Add the meatballs and cook another 5 minutes.

Season to taste with salt and black pepper, maybe even a pinch of red pepper flakes and a squirt of lemon juice. Put some pasta in each bowl & ladle the soup on top of that. Serve immediately. Top with parmesan if desired.

Leftovers will keep in a sealed container in the refrigerator for up to 3 days. To reheat, simmer gently over low heat.

Traditionally there is an egg or 2 mixed into the broth. You can do this if you wish. All you need to do is whisk it in, forming strands at the last minute of cook time.