Cook the pasta: Bring a large pot of salted water to a boil and cook the penne according to the package directions until al dente. Reserve 1 cup of the pasta water, then drain.

Sear the chicken: Season the diced chicken with garlic powder, half the salt, and half the pepper. Heat the olive oil in a large skillet over medium-high heat and cook the chicken for 5-6 minutes, stirring occasionally, until browned and it reaches 165°F. Remove to a plate.

Sauté the aromatics: Melt the butter in the same skillet. Add the garlic and sun-dried tomatoes and cook for 1 minute until fragrant.

Build the sauce: Pour in the chicken broth, scraping up any browned bits from the bottom of the pan. Stir in the heavy cream and parmesan and simmer for 3-4 minutes until slightly thickened.

Wilt the spinach: Add the spinach and stir until wilted, about 1-2 minutes.

Combine: Return the chicken to the skillet along with the drained pasta. Toss to coat, adding a splash of the reserved pasta water if the sauce needs loosening. Season with the remaining salt and pepper to taste.

Serve: Serve warm with extra parmesan on top.