Preheat oven to 200°C (180°C fan forced). Season the chicken drumsticks well with salt and pepper.
Heat a little oil in a large ovenproof pan over medium heat. Add the chicken and cook for 5 to 7 minutes, turning, until browned on all sides. Remove and set aside.
In the same pan, add the sliced onion and cook for 4 to 5 minutes, stirring occasionally, until softened and lightly golden. Add the garlic and cook for 30 seconds until fragrant.
Add the uncooked rice and stir for 1 minute so it coats in the oil. Spread it out evenly. Return the chicken to the pan, nestling it in on top of the rice.
In a jug, combine water, French onion soup mix, chicken stock powder, and dried thyme. Stir well until dissolved.
Pour the liquid evenly over the rice, making sure the rice is mostly covered but the chicken stays sitting on top.
Cover the pan tightly with a lid or foil. Bake for 40 minutes. Remove the cover and bake for a further 10 minutes until the rice is tender and the chicken is cooked through.
Remove from the oven and let it rest for 5 minutes. Fluff the rice gently with a fork, then serve with your choice of sides.