Heat the oil in a large pot over medium heat. Add the diced onion and cook for 3-4 minutes, stirring occasionally, until softened and translucent. Add the minced garlic and cook for another 30 seconds until fragrant. This aromatics base is crucial for building deep flavor—don't skip the garlic cooking step or it can taste raw.

Stir in the tomato paste and chopped sun-dried tomatoes, cooking for about 2 minutes while stirring constantly. This 'blooming' step develops the tomato flavors and removes the raw paste taste. The sun-dried tomatoes add concentrated sweetness and umami that makes this soup special.

Pour in the chicken broth and bring to a boil. Add the heavy cream, basil, salt, Italian seasoning, garlic powder, and red pepper flakes. Stir well to combine, then reduce heat to medium and let simmer for about 12 minutes. This simmering time allows the flavors to meld together and the seasoning to distribute evenly throughout the broth.

Add the pasta to the simmering broth and cook until it reaches al dente (usually about 10-12 minutes, depending on your pasta shape). Stir occasionally to prevent sticking. I prefer to cook the pasta directly in the soup rather than separately—it absorbs the flavors and makes cleanup easier.

Reduce the heat to low and add the fresh spinach, cooked chicken, softened cream cheese, and grated Parmesan cheese. Stir gently and continuously for about 5 minutes until the cream cheese is fully melted and the spinach is wilted. The residual heat will warm the chicken through without overcooking it. I like to cut the cream cheese into small chunks before adding it—it melts more evenly and prevents lumps.

Ladle the soup into bowls and serve immediately. Top each bowl with extra freshly grated Parmesan, a sprinkle of fresh or dried basil, and a pinch of red pepper flakes for those who like heat.