Remove the center of the apple, using an apple corer. Place the apple onto a large square of double layered kitchen foil.
Mix together the brown sugar and cinnamon and pack into the core of the apple. Wrap the apple and gather together the foil to make a handle.
At the barbecue:
Place the apples on their sides, directly onto the coals and place the lid onto the barbecue. Cook for a total of 10 minutes, until soft and tender. Using tongs, quarter turn the apples throughout the cooking time.
Open out the foil, being careful of the hot sugar. Serve in the foil with a good lug of double cream. For a slightly sweeter apple, add a spoonful of either honey or golden syrup before cooking.