Bring a large pot of salted water to a boil. Cook pasta according to package directions until al dente, about 10 to 11 minutes for penne. Before draining, reserve 1/2 cup of pasta water. Drain and set aside.

Heat olive oil in a large skillet over medium-high heat. Season chicken with salt and pepper. Cook for 5 to 6 minutes, turning occasionally, until golden brown and cooked through to an internal temperature of 165 degrees F. Remove chicken and set aside.

In the same skillet, add minced garlic and chopped sun-dried tomatoes. Saute for 1 minute until fragrant. Stir in Italian seasoning and red pepper flakes if using. Watch the garlic closely to avoid burning.

Pour in the chicken broth and bring to a gentle simmer, scraping up any browned bits from the bottom of the pan. Let simmer for about 2 minutes to reduce slightly.

Reduce heat to low. Stir in the heavy cream and Parmesan cheese, whisking steadily until the sauce is smooth and creamy. Do not let the sauce boil.

Return the cooked chicken to the skillet and add the baby spinach. Simmer gently for 2 to 3 minutes until the spinach wilts and the sauce thickens slightly.

Add the cooked pasta and toss to coat evenly in the sauce. Add reserved pasta water a splash at a time if needed to loosen the sauce. Serve warm topped with extra Parmesan and fresh basil or parsley.