Boil the Pasta: Bring a large pot of salted water to boil. Add pasta and cook until al dente, about 8-10 minutes. Reserve ½ cup pasta water and drain the rest.

Cook the Chicken: Season chicken breasts with garlic powder, salt, and pepper. Heat a skillet over medium heat, add olive oil and butter. Cook chicken for 5-6 minutes per side until golden brown and cooked through.

Prepare the Sauce Base: In the same skillet, reduce heat to medium-low, sprinkle in flour, and stir for about 1 minute until fragrant. Scrape any brown bits from the bottom.

Create the Creamy Sauce: Gradually whisk in chicken broth, followed by heavy cream. Once smooth, add pesto, lemon juice, and sun-dried tomatoes, and let simmer for 3-4 minutes until thickened.

Add the Spinach: Fold in fresh spinach and cook for another 2-3 minutes until wilted.

Combine with Pasta: Add drained pasta to the skillet, tossing to coat. Use reserved pasta water to adjust sauce consistency if needed.

Serve with Chicken: Slice cooked chicken and place on top of the pasta. Garnish with Parmesan cheese if desired, and serve immediately.