Lay the ribs in a roasting tin and rub all over with 2 tbsp of the jerk spice mix. Leave to marinate for at least 2 hrs, or preferably overnight.
Heat oven to 160C/140C fan/gas 3. Put the ribs in a clean roasting tin, season and pour over 500ml of the pineapple juice. Cover the tin with foil and bake for 2 hrs.
Mix the remaining jerk spice mix, pineapple juice, sugar, vinegar, lime juice and a good pinch of salt in a saucepan. Heat until the sugar dissolves, then bubble until thick and sticky.
To make the rice, heat the oil in a large pan or wok. Add the pepper, and stir-fry until softened. Add the pineapple, brown sugar and plenty of seasoning, and continue cooking until the pineapple starts to caramelise.
Remove the ribs from the oven and pour away the cooking liquid. Increase oven to 200C/180C fan/gas 6. Pat the ribs dry with some kitchen paper, then brush the jerk sauce all over them.
Return to the oven for 20 mins, brushing with any remaining sauce every 5 mins or so, until the ribs are really sticky.
Add the cooked rice to the pan with the pineapple and vegetables, stir-fry for a further 2 mins, stirring occasionally, then add the coriander. Serve with the sticky ribs.