Heat 1 tablespoon of oil from the sun-dried tomato jar in a large pot over medium heat. Add chopped onions and garlic, sauté for about 4 minutes until softened and fragrant.
Stir in the tomato paste and sun-dried tomatoes, cooking for another 2 minutes to develop the flavors.
Pour in the chicken broth, heavy cream, salt, Italian seasoning, garlic powder, and crushed red pepper. Bring to a gentle simmer for 12 minutes, stirring occasionally.
Add the uncooked pasta and continue simmering for another 12 minutes, or until the pasta is al dente.
Stir in the chopped spinach and cubed cream cheese, allowing it to melt into the sauce for about 5 minutes.
Add shredded rotisserie chicken or top with slices of pan-seared chicken.