Prepare the Meatballs Using your hands, gently stir together ground chuck, sausage, onion, Parmesan, egg, garlic, breadcrumbs, dried basil, fennel seeds, salt, and pepper in a large bowl, being careful not to overwork. Divide mixture into about 24 (1-ounce) portions (about 2 tablespoons each), and roll into 1-inch balls. Place in an even layer on a baking sheet; set aside.

Prepare the Soup Heat oil in a large Dutch oven over medium-high. Working in 2 batches, add half of Meatballs in an even layer; cook, turning as needed, until lightly browned on all sides, about 4 minutes per batch. Transfer to a baking sheet using a slotted spoon.

Add onion, carrot, and celery to remaining oil in the Dutch oven; cook over medium-high, stirring occasionally, until softened and beginning to brown, 5 to 8 minutes. Add Italian seasoning, and cook, stirring constantly, until fragrant, about 30 seconds. Add white wine; cook, using a wooden spoon to scrape browned bits from bottom of Dutch oven, until reduced slightly, about 1 minute. Stir in broth and salt; bring to a boil over medium-high, stirring occasionally. Reduce heat to medium, and stir in broken lasagna noodles and seared Meatballs; cook, stirring occasionally, until noodles are tender and a thermometer inserted into Meatballs registers at least 160°F, 12 to 15 minutes. Stir in spinach, Parmesan, and cream; cook, stirring constantly, until spinach is wilted, about 1 minute. Ladle into bowls; garnish with mozzarella, ricotta, basil, and additional Parmesan.