1: Set up your grill for spit-roasting and heat it as hot as it will go. On a charcoal grill, rake the coals under the spit (not just in front and back as we usually do for rotisserie grilling). On a gas grill, light the burners under the spit as well as behind it.

2: Make the spiced sugar: Combine the sugar, cinnamon, allspice, and cloves in a pie plate or other shallow dish large enough to accommodate the pineapple, and mix well with your fingertips or a whisk.

3: Peel the pineapple, then turn it on its side. Remove the eyes by making V-shaped cuts on a diagonal on the sides of the pineapple. Core with a pineapple corer. Skewer it on the spit. The spit will pass right through the tunnel in the center. Use the prongs to hold the pineapple in place.

4: Using a basting brush, paint the pineapple on all sides with the molasses, then dredge it on all sides in the sugar mixture. Don’t forget the ends. Sprinkle with salt. Immediately put the pineapple on the grill, attaching the spit to the motor according to the manufacturer’s directions.

5: Spit-roast the pineapple until the outside is darkly browned, 8 to 12 minutes. The sugar should cook to a dark caramel crust. You’ll probably want to help it brown with a blowtorch or roofer’s torch. The idea is to sear the exterior while keeping the fruit cool and moist in the center.

6: Carefully unskewer the pineapple on a rimmed sheet pan and stand it upright on a round flameproof serving platter. Pour the 151-proof rum in the center where the core was. Light it with a long-stemmed match. Let it burn for a while (there’s your volcano), then cut the pineapple in 4 pieces, either crosswise or lengthwise. Serve in heatproof bowls with ice cream or whipped cream on the side if you like, spooning the now extinguished rum over the fruit.