Preheat the oven to 375F.

Prepare the chicken thighs by seasoning the skin with salt and pepper. Place them in a hot skillet, skin-side-down, for five minutes or until starting to crisp up. You can skip this step if using skinless thighs.

Transfer the chicken to a small baking dish and roast for 15 minutes.

As soon as you've got them in the oven, start the sauce. Wipe any excess grease from the skillet, then add the diet coke or cola, together with the tomato sauce, Worcestershire sauce, and liquid smoke. Cook over a medium-high heat and let it bubble. The sauce will reduce by about half.

Remove the chicken from the oven and carefully drain any excess fat. Pour the sauce over the chicken and return it to the oven. Roast until an internal temperature of 165F is reached - about 10-15 minutes depending on the size of the chicken pieces.

Transfer the cooked chicken to the serving plates and pour some of the sauce over the top. Garnish with parsley.