Place the bread crumbs and milk in a bowl and stir together to allow the bread to absorb the milk for an extra moist breadcrumb.
Add in the ground beef, sausage, Italian seasoning, pepper, salt, eggs, minced garlic, and parmesan cheese. Work together with your hands to combine the meatball ingredients evenly.
Using a teaspoon or melon baller, form small meatballs and place on a baking sheet. We like a smaller meatball for this recipe so that it is bite-sized in our soup. Roll the mixture in your hands to form a smooth, round ball.
Coat the bottom of a non-stick skillet with olive oil. Heat over medium. Cook the meatballs, working in batches, to sear on all sides. They do not need to cook through, but should develop a nice, golden brown crust (2-3 minutes per batch). Set the meatballs aside.
Meanwhile, heat another tablespoon of olive oil in a large soup pot. Add diced celery, onion, and carrots, and cook until the onion is translucent and the vegetables have begun to soften.
Add the minced garlic, salt, and pepper and saute 1 minute longer.
Add the chicken broth to the pot and bring mixture to a boil. Taste the broth and add additional salt and/or pepper, if desired.
Add the pasta and meatballs to the soup and simmer over low heat for 10-12 minutes, until the pasta is tender and the meatballs are cooked through.
Stir in the spinach and remove the soup from heat. The spinach will wilt right away.
Serve with freshly grated parmesan cheese.
Notes
We made about 42 meatballs - teaspoon size was perfect - about ¾ inch round.
The meatballs can be dropped straight into the soup without being browned first. This will take away some of the flavor and will require an extra few minutes of cook time, but it’s perfectly fine to skip the pan-searing.
Acini di pepe is a small pasta, similar in size to pearl couscous. It soaks up a good amount of broth - ½ cup - ¾ cup will leave you with some broth in your soup. You can substitute with other small pasta such as orzo or ditalini if preferred.
We recommend using standard chicken broth or making your own broth with bouillon/water. Using a low sodium chicken broth will give you a soup that is lacking proper seasoning. When you have enough salt in the broth, all of the other flavors are also enhanced.
The meatballs are made with a combination of hot Italian sausage and ground beef which lends plenty of flavor and adds a dash of spice. You can substitute with any combo of meat you prefer. If you choose to use ground turkey or chicken, I would recommend adding more seasonings as they have less flavor and can be bland otherwise.
Greens that might be substituted for the spinach include escarole, kale, or chard. These greens may need to simmer a few minutes to wilt properly as opposed to the spinach which is immediate.