Heat the oven to 200C/180C fan. Put a roasting tin or ovenproof dish on the hob with a tablespoon of oil.
Season the chicken thighs with salt, pepper and half the dried thyme. Place them skin-side down in the hot tin and brown for 5-6 minutes until the skin is golden. Remove them to a plate.
Add the chopped onion to the same tin and cook for 3-4 minutes until softening. Add the garlic and rice, stir for a minute to coat the rice in the oil.
Pour in the hot stock, lemon zest, lemon juice, oregano and remaining thyme. Stir once, then place the chicken thighs on top, skin-side up.
Cover tightly with foil and bake for 25 minutes. Remove the foil and bake for another 10-15 minutes until the chicken skin is crisp and the rice has absorbed all the liquid.
Scatter with chopped parsley if you have some and serve straight from the tin. A green vegetable on the side is nice but not essential.