Cook the pasta: Bring a large pot of salted water to a boil. Cook the penne according to package directions until al dente. Reserve about 1/2 cup of pasta water, then drain the pasta and set aside.
Season the chicken: Pat the chicken breasts dry with paper towels. In a small bowl, combine the paprika, garlic powder, onion powder, thyme, oregano, cayenne pepper, salt, and black pepper. Rub the seasoning generously over both sides of the chicken.
Blacken the chicken: Heat the olive oil in a large skillet over medium-high heat. Add the seasoned chicken and cook for about 5–7 minutes per side, depending on thickness, until deeply browned and cooked through to an internal temperature of 165°F.
Rest and slice: Transfer the cooked chicken to a cutting board and let it rest for 5 minutes before slicing it into strips or bite-sized pieces.
Sauté the garlic: Reduce the skillet heat to medium-low. Add the butter and minced garlic, cooking for about 30 seconds until fragrant. Avoid browning the garlic.
Make the Alfredo sauce: Pour in the heavy cream and stir well, scraping up any flavorful browned bits from the bottom of the skillet. Let the cream gently simmer for 2–3 minutes.
Add the Parmesan: Reduce the heat to low and gradually stir in the freshly grated Parmesan until completely melted and the sauce is smooth. Season with salt, black pepper, and optional red pepper flakes.
Combine with the pasta: Add the cooked penne to the skillet and toss until every piece is evenly coated in Alfredo sauce. If the sauce is too thick, add reserved pasta water one tablespoon at a time until it reaches your desired consistency.
Finish the skillet: Arrange the sliced blackened chicken over the creamy penne. Garnish with chopped fresh parsley and additional Parmesan cheese.
Serve immediately: Serve while hot and creamy for the best texture and flavor.