Begin by bringing a large pot of salted water to a rolling boil. Once boiling, add your fettuccine and cook according to the package instructions until al dente, typically around 8-10 minutes. Reserve ½ cup of the starchy pasta water before draining the rest in a colander.

While the pasta cooks, slice the chicken thinly and season with garlic powder, salt, and pepper. Heat olive oil and butter in a large skillet over medium-high heat. Once the butter is melted, add the chicken slices. Cook for about 5-6 minutes per side until golden brown and cooked through. Remove the chicken and set aside.

In the same skillet, sprinkle in the all-purpose flour. Stir continuously for about 1 minute until a light golden roux forms, absorbing flavors from the pan.

Gradually pour in the chicken broth while whisking to prevent lumps. Continue stirring as you add the heavy cream, basil pesto, lemon juice, and sun-dried tomatoes. Allow the mixture to simmer gently for about 3-5 minutes until thickened.

Once your sauce is simmering, fold in the fresh baby spinach. Stir until the spinach has wilted down, which should take about 2-3 minutes.

Add the drained fettuccine directly to the skillet with the creamy spinach sauce. Toss gently to coat the pasta thoroughly, adding reserved pasta water if needed for consistency.

Slice the resting chicken and place it on top of the creamy fettuccine. Optionally sprinkle with grated Parmesan cheese and a twist of lemon zest. Serve immediately.