Dice the onion into 1/2-inch pieces and set aside. In a large skillet over medium-high heat, brown the ground beef, breaking it apart as it cooks and seasoning generously with salt and pepper. This should take about 5-7 minutes until no pink remains. I like to use lean ground beef because it renders less grease, which keeps the soup lighter and cleaner-tasting. Once browned, transfer the beef to your crockpot.

To the crockpot with the browned beef, add the marinara sauce, diced tomatoes, diced onion, beef broth, garlic powder, onion powder, Italian seasoning, oregano, paprika, and red pepper flakes. Stir well to combine all ingredients and distribute the spices evenly throughout the liquid. This layering of aromatics and seasonings early on allows the flavors to develop and meld together as the soup simmers.

Cover the crockpot and cook on high for 3 hours. This extended cooking time allows the beef to become tender, the onions to soften completely, and all the spices to develop into a rich, complex broth. During this time, you can prepare your yogurt and cheese components, or simply relax knowing the hard work is done.

Break the lasagna sheets into 2-inch pieces. After the 3-hour simmer, stir the broken pasta pieces into the hot soup, followed by the Greek yogurt and mozzarella cheese. I prefer Fage Greek yogurt because it has a thicker, creamier texture that doesn't separate as easily in the hot broth compared to regular yogurt. Stir everything together until the yogurt is fully incorporated and the cheese begins to melt into the soup.

Cook the soup uncovered on high for another 15-20 minutes, stirring occasionally, until the pasta pieces are tender and the soup has thickened slightly from the cheese and yogurt. Ladle the soup into bowls and top each serving with a dollop of ricotta cheese, fresh basil, and a sprinkle of Parmesan. The cool ricotta and fresh basil provide a nice textural and flavor contrast to the warm, creamy soup.