Pre-heat the oven to 180C / 360F
Pour out and cover the bottom of your baking dish with the rice.
Season the chicken thighs generously with salt & pepper (plus any other herbs or spices you choose).
Melt ⅓ of the butter and the olive oil over a high heat in a frying pan or skillet. Sear the chicken on both sides until lightly browned. (You are not cooking the chicken all the way through, it will cook later in the oven).
Remove the chicken from the pan and arrange in a single layer over the rice in the baking dish.
Lower the heat under the frying pan to medium and add the remaining butter.
Add the garlic to the pan and cook for a couple of minutes until soft.
Add the chicken stock, lemon juice, parmesan, cream, and spinach. Stir and bring to the boil.
Lower the heat and simmer for 10 minutes until the sauce has slightly thickened and the spinach has melted.
Pour the sauce over the chicken in the baking dish. If you like, you can decorate with some lemon slices.
Place in the oven and bake for 40 minutes.
Serve with a simple side salad.