Brown the Italian sausage in a cast iron skillet until cooked through and no longer pink, then drain well. Visual cue: sausage should have browned crumbles and the pan juices should look mostly clear.

Add the browned Italian sausage to the Crockpot with the diced onion, minced garlic, crushed tomatoes, diced tomatoes, chicken broth, tomato paste, Italian seasoning, dried basil, and red pepper flakes. Visual cue: the mixture should look evenly speckled with seasonings and glossy from the tomato paste.

Cook on Low for 5-7 hours (or on High for 2.5-3 hours). Visual cue: broth should be gently bubbling around the edges and the flavors should look cohesive.

In the last 30-35 minutes, add the broken gluten-free lasagna noodles (or GF penne). Visual cue: pasta should start to sink and then soften as the soup simmers.

If needed, increase to High so the soup maintains a steady simmer while the GF pasta cooks until tender; check frequently to prevent overcooking. Visual cue: noodles should be tender without turning mushy.

Season the soup with salt and pepper to taste. Visual cue: taste should round out and the tomato flavor should become more pronounced.

Mix the cheese dollop by combining ricotta, shredded mozzarella, parmesan, and chopped fresh basil. Visual cue: the mixture should be thick and spoonable with visible basil flecks.

Serve the soup in bowls with a generous dollop of the cheese mixture on top. Visual cue: the dollop should begin to melt slightly into the hot broth.