In a large pot, bring salted water to a rolling boil. Add your preferred short pasta and cook according to package instructions until al dente, usually about 8-10 minutes. Reserve ½ cup of the pasta water to adjust the sauce later, then drain the pasta and set it aside.

Season sliced chicken breasts with garlic powder, salt, and pepper. In a skillet, heat olive oil and butter over medium-high heat. Cook chicken for about 5-6 minutes on each side until golden brown and cooked through. Let the chicken rest and then slice into bite-sized pieces.

In the same skillet, sprinkle flour, stirring for 1 minute to create a roux. Gradually add chicken broth while stirring to scrape up browned bits. Pour in heavy cream, followed by pesto, lemon juice, and sun-dried tomatoes. Simmer for 3-5 minutes until thickened.

Gently fold in fresh baby spinach into the simmering sauce, stirring until wilted for about 2-3 minutes.

Carefully add the drained pasta to the skillet with the sauce, tossing to coat. If too thick, gradually add reserved pasta water. Fold in sliced chicken.

Plate immediately, garnishing with freshly grated Parmesan cheese, if desired. Serve hot.