In a large skillet over the stove top, add the Italian sausage, diced onion, and minced garlic. Cook over medium-high heat while crumbling the sausage until sausage is no longer pink and is cooked through completely.
Add Italian seasoning, rosemary, chicken broth, Italian diced tomatoes, tomato sauce, sugar, salt and pepper and stir well.
Break each lasagna noodle into 6 equal pieces and arrange evenly in the skillet. Push the noodles under the liquid so they're covered completely. Bring the mixture to a full rolling boil, cover the skillet and allow it to continue to boil. Stir it every 5 minutes or so, ensuring that the noodles are covered by the liquid before you cover the skillet again. Allow it to boil just until the noodles are nice and tender when poked with a fork and the liquids have reduced so the mixture is no longer soupy.
Top with dollops of ricotta distributed all around, then sprinkle with shredded mozzarella. Serve and enjoy!