Prepping the glaze – whisk rum, brown sugar, cinnamon powder, vanilla extract well. Marinade pineapple – Soak pineapple slices in rum, brown sugar liquid for about 30 minutes or even over night.
Grilling fruit – heat up the grill pan. Wipe the pan with some oil or butter using a paper towel. Place rum soaked pineapple on hot grill, cook pineapple for 3 to 4 minutes on medium heat. If you are looking for beautiful cross grill marks rotate pineapple slices on the same side 45 degree. Cook for 3 minutes.
Flip the pineapple slices and cook for 3 minutes on the other side. You can rotate it 45 degree on the other side as well to get cross marks.