You will also need 6 x 150ml moulds, such as plastic or metal pudding/jelly moulds, tea cups or ramekins, lightly greased with vegetable oil.
IN THE KITCHEN:
Soak the gelatine leaves in cold water for 5 minutes to soften.
Place the coconut milk, cream and sugar in a saucepan. Gently bring to the boil, stirring occasionally. Remove from the heat. Squeeze out the excess water from the gelatine leaves and stir into the pan. Leave to cool for 5 minutes before stirring in the yoghurt until smooth, using a balloon whisk if necessary. Pour into the oiled moulds and leave to set in the fridge for about 3 hours or overnight (if you can).
Trim the top and bottom from the pineapple and stand upright. Using a sharp knife, slice off the skin. Cut the pineapple into quarters lengthways, then cut out the central core before slicing each piece into around 6 pieces. Sit on a tray lined with paper towel to absorb some of the juice.
ON THE BARBEQUE:
Prepare the barbeque with the baffle down, set at a hot temperature for grilling (about 250-350°C).
Put the caster sugar and rum in a heavy based saucepan and sit on the barbeque. Bring to the boil, stirring until the sugar has dissolved. Simmer for a minute or so then remove from the heat.
Brush the pineapple pieces with the syrup, then place them directly on the grill. Cook for about 2 minutes until you have char lines before turning. Brush again with the syrup and cook again until evenly charred and tender.
Turn the set panna cotta out on to plates, or leave in teacups if that’s what you’ve used. If they won’t come very easily, then slide a sharp knife down the side to break the air seal or very briefly dip the moulds into hot water. Sit some pineapple on the side of the plates and finish by pouring over some rum syrup.