Preheat your oven to 400°F.
In a small bowl, combine the juice and zest of the lemon, minced garlic, dried thyme, salt, and pepper. Drizzle in the olive oil and mix to form a marinade.
Place the chicken breast on a baking tray and rub the marinade evenly over it. Let it sit while you prepare the pilaf.
Roast the chicken in the preheated oven for about 20-25 minutes or until fully cooked and the internal temperature reaches 165°F.
Meanwhile, in a saucepan over medium heat, add a small drizzle of olive oil and sauté the chopped onion and carrot until they soften, about 3-4 minutes.
Stir in the cooked basmati rice, allowing the vegetables to mix thoroughly with the rice. Season lightly with salt and pepper. If desired, add a splash of water or low-sodium broth to keep the pilaf moist.
Cover the pan and let the rice warm through for about 5 minutes. Fold in the chopped fresh parsley.
Once the chicken is done, let it rest for a couple of minutes before slicing.
Plate the sliced chicken alongside a generous serving of rice pilaf and garnish with extra parsley or a lemon wedge if desired.