Bring a large pot of salted water to a rolling boil. Add the dried penne pasta and cook according to package instructions until al dente, usually around 10–12 minutes. Once cooked, drain the pasta in a colander, but be sure to set aside ½ cup of the pasta water for later use.

In a large frying pan, heat vegetable oil over medium-high heat. Add the sliced chicken breast in a single layer, cooking it undisturbed for about 4 minutes until golden brown. Carefully flip the chicken pieces and cook for another 2 minutes until cooked through.

Reduce the heat to medium and add the minced garlic and sun-dried tomatoes. Stir in the butter and sauté for about 1 minute until fragrant.

Pour in the chicken stock and bring it to a gentle simmer. Allow the mixture to bubble for about 2 minutes.

Reduce the heat to low and stir in the thickened cream. Let it simmer for about 3–5 minutes until it thickens slightly.

Add the drained penne pasta and fresh baby spinach to the pan. Toss together gently for about 1-2 minutes until the spinach has wilted and the pasta is coated with the sauce.

Sprinkle in the grated Parmesan cheese and stir to combine. Cook for an additional minute to melt the cheese into the sauce.

Remove from heat and scoop the creamy chicken spinach penne into serving bowls. Top with additional grated Parmesan or freshly chopped parsley if desired. Serve hot.