Brown the Italian sausage in a cast iron skillet over medium-high heat until cooked through, then drain off excess fat and set aside briefly. You should see browned bits on the meat and no pink remaining.

Add the browned sausage to the crockpot along with the diced onion and minced garlic. Stir briefly so the onion and garlic are coated in the drippings.

Pour in the crushed tomatoes and diced tomatoes, then add the chicken broth, tomato paste, Italian seasoning, dried basil, and red pepper flakes. Make sure everything is evenly combined for consistent flavor.

Cook on Low for 5-7 hours, or High for 2.5-3 hours. The broth should look simmering and well developed by the end.

In the last 30-35 minutes, add the broken gluten-free lasagna noodles or GF penne. Increase to High if needed so the pasta cooks through on schedule.

Cook until the GF pasta is tender, checking frequently because GF pasta can overcook. Stop as soon as it’s just tender—some slight firmness is okay.

Season with salt and pepper to taste and stir well. Taste and adjust so the tomato broth is balanced.

Mix ricotta, shredded mozzarella, and parmesan to form a thick cheese dollop. It should hold together well enough to sit on the soup.

Serve the soup in bowls and top each serving with a generous dollop of the cheese mixture. Add fresh basil on top so it looks bright and melts slightly from the hot broth.