Begin by bringing a large pot of salted water to a rolling boil over high heat. Add your choice of short pasta and cook until al dente, usually about 8-10 minutes. Reserve a cup of pasta water before draining.

While the pasta cooks, season sliced chicken breasts with garlic powder, salt, and pepper. Heat olive oil and butter in a skillet over medium-high heat. Add chicken and cook for 5-6 minutes on each side until golden brown and cooked through.

In the same skillet, reduce the heat slightly and sprinkle flour over the residual fat. Stir continuously for about 1 minute to form a roux.

Gradually pour chicken broth while whisking to avoid lumps, then add heavy cream. Mix until smooth, allowing to thicken for 3-5 minutes. Stir in pesto and lemon juice.

Add sun-dried tomatoes and spinach, stirring gently until spinach wilts, about 2 minutes.

Toss the drained pasta into the skillet, stirring to coat with the sauce. If too thick, add reserved pasta water to adjust consistency.

Slice the rested chicken and fold it into the pasta. Serve immediately, topping with Parmesan cheese if desired.