Mix all of the marinade ingredients in a large bowl, then take 2 tbsp of this mix and place in a small separate bowl to the side (optional: this is to use to glaze the chicken at the end of cooking.)
Add the chicken thighs to the large bowl containing the marinade and mix together, coating well. Leave covered, in the fridge, for as long as you have (maximum 12 hours). Season with salt and pepper.
When ready to cook: pre-heat the oven to 180℃ fan/350F, 200℃/400F or Gas Mark 6.
Bake the chicken thighs in a baking dish for 20 – 25 minutes or until the chicken is cooked through. Optional: brush the chicken with the marinade you kept back earlier. Pre-heat the grill to high and pop under the grill for 3 – 5 minutes until the chicken is browned a little on top (be sure your dish is grill safe if doing this!)
Scatter over the parsley and wiggle in a few extra lemon slices before serving.