Start by heating olive oil in a large soup pot over medium heat. Add the chopped onion, a pinch of salt, and red pepper flakes. Cook for about 3 minutes until the onion softens and starts to caramelize.
Next, stir in minced garlic and cook for another 3 minutes. Add yellow squash, zucchini, carrots, sun-dried tomatoes, and Italian seasoning. Cook for 3-5 minutes until the vegetables begin to caramelize.
Pour in the chicken or vegetable stock along with the Parmesan rind. Bring the mixture to a boil, allowing the flavors to meld together for a rich base.
Add the broken mafalda corta noodles and simmer for 10 minutes until tender. This helps the noodles absorb the flavors of the creamy broth.
Turn off the heat and stir in fresh spinach, heavy cream, and pesto. Season with salt and pepper to taste. The spinach wilts beautifully in the warm broth.
Ladle the soup into bowls and top with a dollop of ricotta and a drizzle of olive oil. Finish with a sprinkle of freshly ground black pepper for a restaurant-worthy presentation.