In a bowl mix together the ground chicken, breadcrumbs, heavy cream, parmesan cheese, egg, and all of the spices until fully combined.
Spoon a small amount of the chicken mixture into the palm of your hand. Roll the mixture into a ball about 1” in size. Set the ball down on a tray then repeat until all of the mixture has been formed into meatballs.
In the bottom of a soup pot, melt the butter and oil over medium high heat. Working in batches as to not overcrowd, sear the meatballs on all sides. Once all sides have been seared remove the meatballs from the pot.
Once all of the meatballs have been seared, leave the pot on the heat and pour in the carrots, onions, celery, and soup seasonings (except for the fresh parsley).
Sauté the vegetables for 5 minutes, then add in the garlic and sauté for another 5 minutes.
Pour in the white wine vinegar, juices from ½ of the lemon, and chicken broth, bring to a light boil.
Add the meatballs back into the soup, let boil for minutes.
Add the Acini de Pepe pasta and cook until tender.
Carefully taste the soup and add in any additional seasoning as preferred. Depending on the type of chicken broth you used, you may need to add extra salt at this time.
Add in the spinach and fresh parsley just before serving.
Garnish with fresh parsley and a slice from the remaining ½ of the lemon.