1. Prepare the Chicken: Start by slicing the boneless, skinless chicken breasts horizontally to create thinner cutlets, about 1/2 inch thick. In a medium bowl, toss the chicken with olive oil, Italian seasoning, garlic powder, salt, and black pepper until well coated.

2. Cook the Pasta: While the chicken is marinating briefly, bring a large pot of salted water to a rolling boil. Add the penne pasta and cook according to package directions until al dente. Before draining, reserve about 1 cup of the starchy pasta water.

3. Sear the Chicken: Heat a large skillet or Dutch oven over medium-high heat. Once hot, add the seasoned chicken in a single layer, making sure not to overcrowd the pan. Cook for 3-4 minutes per side, or until golden brown and cooked through. Remove the chicken from the skillet and set aside on a plate.

4. Build the Sauce Base: Reduce the heat to medium. Add the butter to the same skillet, letting it melt. Add the chopped onion and cook for 3-4 minutes, stirring occasionally, until it softens and becomes translucent. Then, add the minced garlic and chopped sun-dried tomatoes, cooking for another minute until fragrant.

5. Create the Creamy Sauce: Pour in the chicken broth, scraping up any browned bits from the bottom of the skillet with a wooden spoon. Bring the mixture to a gentle simmer and let it cook for 2-3 minutes, allowing the flavors to meld and the liquid to reduce slightly.

6. Finish the Sauce and Combine: Stir in the heavy cream and grated Parmesan cheese. Continue to simmer gently for 2-3 minutes, stirring constantly, until the sauce thickens slightly and becomes smooth and creamy. If the sauce seems too thick, add a splash of the reserved pasta water until it reaches your desired consistency.

7. Add Chicken and Pasta: Return the cooked chicken to the skillet with the sauce. Add the drained al dente pasta. Toss everything together gently until the pasta and chicken are thoroughly coated in the rich, creamy sauce.

8. Garnish and Serve: Taste and adjust seasonings if necessary. Garnish generously with fresh chopped basil before serving.