Start by heating olive oil in a large soup pot over medium heat. Add onions, a pinch of salt, and red pepper flakes. Cook until onions are soft and slightly caramelized, about 3 minutes.
Next, toss in the garlic and cook for another 3 minutes. Then add yellow squash, zucchini, carrots, sun-dried tomatoes, and Italian seasoning. Stir occasionally until veggies begin to caramelize, about 3-5 minutes.
Pour in your chicken or vegetable stock and add the Parmesan rind. Bring to a gentle boil, then reduce heat and simmer for a few minutes to let flavors meld.
Add broken lasagna noodles to the simmering broth. Cook for 10 minutes or until tender, stirring occasionally to prevent sticking.
Turn off the heat and stir in fresh spinach, heavy cream, and pesto. Taste and adjust salt and pepper as needed.
Ladle the soup into bowls, adding a dollop of ricotta on top. Finish with a drizzle of olive oil and a sprinkle of Parmesan for a restaurant-quality presentation.