In a large Dutch oven, melt 2 tablespoons of unsalted butter over medium heat until frothy. Add the finely chopped medium onion and sauté for about 3-4 minutes, stirring occasionally, until translucent and lightly browned.

Add 3 minced garlic cloves, 2 teaspoons of Italian seasoning, 1 teaspoon of salt, and a pinch of red chili flakes to the Dutch oven. Stir and cook for 1 additional minute.

Pour in 6 cups of low-sodium chicken broth, then add 1 pound of boneless skinless chicken breasts and 1 cup of chopped sun-dried tomatoes. Increase heat to high and bring the mixture to a gentle simmer.

Cover the pot and reduce the heat to low. Allow the chicken to cook for 12-15 minutes, or until its internal temperature reaches 165°F.

Bring a separate pot of salted water to a rolling boil. Add 2 cups of short dry pasta or broken lasagna noodles, cooking until al dente, about 8-10 minutes. Drain and set aside.

Remove the chicken from the pot and let it cool slightly. Using two forks, shred the chicken into bite-sized pieces.

In a small bowl, whisk together 1 cup of half-and-half with 2 tablespoons of cornstarch until smooth. Gradually stir into the broth and cook for 1-2 minutes.

Stir the shredded chicken, cooked pasta, and 2 cups of fresh spinach back into the pot. Heat through for about 3-5 minutes.

Ladle the soup into bowls and garnish with dollops of ricotta cheese, freshly grated Parmesan, or shredded mozzarella.