Pat the chicken dry and season lightly with salt and pepper.
In a large skillet, heat the olive oil over medium heat. Add the chicken and cook until golden and cooked through, about 6–7 minutes per side depending on thickness. Remove from the pan and let rest for a few minutes, then slice into bite-sized pieces.
In the same pan, add the minced garlic and sauté for about 30 seconds until fragrant.
Stir in the orzo and toast for 1–2 minutes, until it starts to turn a light golden color.
Pour in the chicken broth and bring to a simmer. Cook the orzo, stirring occasionally, until it’s al dente and most of the liquid is absorbed, about 8–10 minutes.
Return the chicken to the pan. Add the spinach and allow it to wilt, about 1–2 minutes.
Zest the lemon directly into the pan, then squeeze in the juice. Stir to combine.
Finish with grated parmesan, crushed red pepper if using, and a final taste of salt and pepper. If the sauce seems thick, loosen with a splash of broth or a bit of water.
Garnish with chopped parsley and serve hot. A simple green salad on the side works nicely.