Sauté the Aromatics
Heat olive oil in a large pot over medium heat. Add diced onion and cook until translucent, about 4-5 minutes. Stir in minced garlic and sauté for an additional 1-2 minutes until fragrant.
Cook the Chicken
Season chicken breasts with salt and pepper. Place them in the pot and sear on both sides until golden brown, about 3-4 minutes per side.
Simmer the Chicken
Pour in chicken broth and bring to a boil. Reduce heat, cover, and let it simmer for about 15 minutes, or until the chicken is fully cooked.
Shred the Chicken
Remove the chicken from the pot and shred it with two forks. Set aside.
Create the Creamy Base
Add heavy cream, sun-dried tomatoes, and Italian seasoning to the pot. Stir well and bring to a gentle simmer.
Cook the Pasta
Stir in the pasta and cook according to package instructions, usually 8-10 minutes, until al dente.
Finish the Soup
Add the shredded chicken back to the pot along with baby spinach, Parmesan cheese, and red pepper flakes. Stir until the spinach wilts and the soup is heated through, about 2-3 minutes.
Season and Serve
Taste and adjust seasoning with additional salt, pepper, or red pepper flakes, as needed.
Garnish and Enjoy
Serve the soup hot, garnished with fresh basil and extra Parmesan cheese if desired.