Make the meatballs: In a large bowl, add the ground chicken, egg, parmigiano reggiano (or parm), breadcrumbs, parsley, basil, dried oregano, garlic powder, italian seasoning, salt, black pepper, and red pepper flakes. Use clean hands to mix until well combined, but avoid over mixing the meatballs or they will become tough. Form the mixture into meatballs about the size of a marble; 40 to 50 meatballs total. Tip: Dip your hands in a bowl of water between each meatball to prevent sticking and to create nice round balls – trust me, it helps!
In a large pot over medium-high heat, warm 1 to 2 tablespoons of olive oil. Once oil is hot, add the meatballs in batches, spacing meatballs about ½ inch apart and brown on all sides, about 5 minutes total. Use a spoon or tongs to carefully transfer meatballs to a plate and set aside. Add more oil, if necessary, between batches, and repeat with the remaining meatballs. Meatballs will finish cooking in the soup, so do not worry if they aren’t fully cooked.
Make the soup: In the same pot, warm 1 tablespoon olive oil over medium heat. Once oil is hot, add in the onions and carrots and saute, stirring occasionally, until softened, 3 to 5 minutes. Next, stir in the garlic, Italian seasoning, and salt, and sauté, stirring constantly, until fragrant, about 1 minute. Add the broth and pearl couscous and stir until well-combined. Use a large spoon to gently drop in a few meatballs at a time until they are all in the pot. Bring the broth to a gentle boil, then reduce the heat and simmer uncovered until the meatballs are cooked through, about 10 to 15 minutes. During the last few minutes of cooking, stir in the chopped spinach and cook until wilted, then remove soup from the heat.
Taste and add more salt and pepper, if needed, then ladle soup into bowls and top with fresh grated parmigiano reggiano and a little fresh chopped parsley. Serve warm with crusty bread or toasted bread for dipping.
To store: Let the soup cool completely, then store it in an airtight glass container in the fridge for up to 5 days.