01 - Cook penne or fettuccine in a large pot of salted boiling water until al dente. Reserve 1/2 cup of pasta cooking water, then drain the pasta and set aside.
02 - While pasta cooks, pat chicken breasts dry and season both sides evenly with salt, black pepper, and Italian herbs.
03 - Heat olive oil in a large skillet over medium-high heat. Add the seasoned chicken breasts and sear for 5 to 6 minutes per side, or until deeply golden and fully cooked. Transfer to a plate and let rest for 5 minutes; slice thinly against the grain.
04 - In the same skillet, melt unsalted butter over medium heat. Add minced garlic and sauté for 1 minute, stirring constantly until aromatic.
05 - Stir in heavy cream, chicken broth, sun-dried tomatoes, and grated Parmesan. Simmer for 2 to 3 minutes, stirring frequently, until the cheese is fully melted and the sauce is smooth.
06 - Add the chopped baby spinach and cook just until wilted, about 1 minute. Season the sauce with crushed red pepper flakes, salt, and black pepper to taste.
07 - Return the sliced chicken to the pan. Add the drained pasta and gently toss everything together to coat in the sauce. If the sauce is too thick, mix in reserved pasta water gradually until desired consistency is reached.
08 - Serve immediately while hot, garnished with extra Parmesan and fresh basil if desired.