In a saucepan (more fakery, the traditional way to jerk anything is over a barbecue grill) fry the onion and garlic in a tablespoon of oil until softened, up the heat and fry off the marinated chicken pieces to give them a little colour. Add the mushrooms and pepper and stir these in to coat them in the jerk seasoning. Simmer for about ten minutes, the mushrooms will release their moisture so you shouldn’t really need any more liquid. The veg are just to bulk this up a little and act as a carrier for the seasoning. You can use whatever you like.