Start by bringing a large pot of salted water to a boil. Add your choice of pasta and cook until al dente, about 8-10 minutes. Reserve 1/2 cup of pasta water and drain the rest.

Season sliced chicken breasts with garlic powder, salt, and pepper. In a skillet, heat olive oil and butter over medium-high heat. Add chicken and cook for 5-6 minutes per side until golden brown and cooked through. Remove from heat and let rest.

In the same skillet, sprinkle in flour and stir to create a roux. Gradually add chicken broth and heavy cream, stirring continuously. Add pesto and lemon juice, then stir in sun-dried tomatoes and let simmer for 3-5 minutes until slightly thickened.

Toss in fresh spinach, stirring until wilted, about 1-2 minutes.

Fold the drained pasta into the skillet, ensuring it's evenly coated with sauce. If too thick, add reserved pasta water until desired consistency is reached.

Slice the rested chicken and place on top of the pasta. Optionally, sprinkle with Parmesan cheese and serve warm.