
Combining the best parts of a lasagna and a big, comforting bowl of soup, lasagna soup is worth making part of your regular meal rotation.
Heat oil in a large Dutch oven or pot over medium heat. Add onion and garlic. Season with salt and pepper. Cook, stirring occasionally, until softened, 4 to 6 minutes. Add sausage and cook, breaking it into pieces, until browned, 5 to 7 minutes. Add tomato paste, oregano, and basil, and cook, stirring, 1 minute. Add marinara and stock; bring to a boil. Add noodles and spinach. Cook until noodles are soft, 10 to 12 minutes.