Brown and drain the sausage well to keep the soup light and let the tomato flavors shine., Taste before adding salt, as canned tomatoes and broth often contain enough salt., Cook lasagna noodles just until tender to avoid mushiness; noodles soften further as soup cools., To reheat leftovers, add extra chicken stock to loosen the soup and add cheese just before serving., For slow cooker method: brown sausage and onions first, then cook all ingredients except noodles and cheese on low for 7–8 hours or high for 3–4 hours; cook noodles separately and add before serving., Veggie variations: add finely chopped zucchini, carrots, mushrooms with onions for extra nutrition., Meat substitutions: ground beef, turkey, or pork can replace Italian sausage by adding extra Italian seasoning to maintain flavor., Pasta substitutions: use ziti, rigatoni, fusilli, or broken penne instead of lasagna noodles., To freeze: freeze soup base without noodles or cheese, thaw, cook fresh pasta separately, then combine with cheeses before serving.