Season the ground beef with salt. Heat the oil in a large pot over medium-high heat. Add the ground beef and arrange it in one layer. Cook for 3 minutes. Stir it well and arrange in one layer again. Cook for 2 minutes. Now, stir and break up any large pieces.
Drain the excess grease in the pot (see notes).
Add the onions and cook for 3 minutes, until they start to soften. Stir often.
Add the garlic, tomato paste, Italian seasoning, and black pepper to the pot and cook for 1 minute while stirring.
Add the diced tomatoes and the chicken broth to the pot and stir while gently scraping any bits on the bottom of the pot.
Raise the heat to high and bring the soup to a simmer (will take about 5-7 minutes). Then, lower the heat to medium-low, cover the pot and cook for 15-20 minutes to allow the flavors to develop and come together. Stir occasionally and keep the broth at a simmer, raise or lower the heat as needed.
Next, add the broken lasagna noodles to the pot. Raise the heat and let it come back to a simmer. Then lower the heat to medium-low, cover, and cook for 30 minutes, or until the noodles are very tender.
Keep the liquid simmering, raise or lower the heat at needed. Stir the soup occasionally, especially as it starts to thicken to keep the noodles from sticking to the bottom.
When the soup is almost ready make the ricotta topping. Add the ricotta and the parmesan cheese to a bowl and stir well until combined.
Taste the soup and add salt if needed. As a reference we did not add extra to ours.
Serve the lasagna soup in individual bowls and top with a tablespoon of mozzarella cheese and a generous dollop of the ricotta parmesan mixture. Garnish with parsley if desired.