In a large pot, heat olive oil over medium heat. Add diced onion, garlic, carrot, and bell pepper. Sauté for about 5-7 minutes, until the vegetables are tender.
Add vegan sausage and cook for an additional 3-4 minutes until it starts to brown.
Stir in the green lentils, crushed tomatoes, vegetable broth, dried basil, dried oregano, red pepper flakes, salt, and black pepper. Bring to a boil, then reduce heat to a simmer. Cook covered for 15-20 minutes or until the lentils are tender.
Add the broken lasagna noodles to the pot and cook according to the package directions (usually about 8-10 minutes) until they are tender.
Serve:
Mix all cheeses in a medium bowl to make the topping.
Ladle the soup into bowls. Top each bowl with a generous amount of cheese mixture and a sprinkle of vegan parmesan.
Garnish with fresh basil before serving.
Notes
Adjust the cooking time of the noodles based on the type used; you may want to add them a few minutes after the soup has started simmering if they take longer to cook but if you don't eat all of the soup at once they will soften more, so al dente is better.
Cooking and storing the noodles separately will help avoid over-softening if you plan to eat the leftovers next day.
Refrigerator: Transfer the lasagna soup to an airtight container and store the cheese topping in a separate container. Refrigerate both for up to 4 days.
Freezer: Note that the noodles will soften quite a bit after freezing. You can freeze the soup and cheese topping separately in airtight containers. Thaw in the refrigerator before reheating.
To reheat: Warm up the soup on the stovetop over medium heat or in the microwave. Add the cheese mixture just before serving.