Heat olive oil in a large skillet over medium-high heat. Add ground beef and cook for 5-7 minutes, breaking it apart with a spoon as it browns. Once the beef is no longer pink, add garlic powder, Italian seasoning, red pepper flakes, salt, and pepper. Stir well to coat the meat evenly with spices, cooking for another minute to bloom the flavors. This upfront seasoning ensures the beef is deeply flavored throughout the soup. Carefully drain excess grease from the skillet, leaving just enough to coat the meat lightly.

Transfer the seasoned beef from Step 1 into your slow cooker. Add beef broth, marinara sauce, and tomato paste, stirring until the tomato paste is fully dissolved and distributed throughout the liquid. The tomato paste adds wonderful depth and richness that pure marinara alone can't deliver. Cover and cook on high for 3-4 hours or on low for 4-5 hours until the broth is simmering gently and the flavors have melded together.

While the soup simmers, combine ricotta and parmesan in a bowl, stirring until well blended. I like to use whole milk ricotta for its creamy texture—it makes the soup feel more luxurious. Set this mixture aside; you'll use half of it to enrich the soup and half for garnish at the end.

After the broth has simmered for the full time in Step 2, add the broken lasagna noodles to the slow cooker, stirring to submerge them in the liquid. Cover and cook on high for 15-30 minutes, checking at the 15-minute mark. The noodles should be tender but still hold their shape—don't overcook or they'll become mushy. Stir occasionally to prevent sticking.

Once the noodles are tender, stir in half of the cheese mixture from Step 3 until it's fully incorporated and creates a creamy texture. Add the spinach and stir well, allowing it to wilt into the warm soup for about 1-2 minutes. Taste and adjust seasonings if needed. I like to reserve the remaining cheese mixture for topping each bowl—this gives you control over how creamy and cheesy each serving is.

Ladle the soup into bowls and top each serving with a generous spoonful of the remaining cheese mixture from Step 3. The warm soup will slightly soften the cheese topping, adding richness without overwhelming the dish. Serve immediately while hot.