Toss the lamb cubes with the jerk seasoning until evenly coated and set aside for 10 minutes.
Heat the oil in a Dutch oven over medium-high heat. Add the lamb and brown on all sides, about 6 to 8 minutes total. Remove the lamb to a plate.
Lower the heat to medium and add the onion, garlic, and bell pepper to the pot. Cook for 4 minutes until the onion softens.
Return the lamb to the pot along with the plantain slices, coconut milk, beef broth, thyme, and allspice. Stir to combine.
Bring the mixture to a gentle simmer, then cover and cook for 1 hour and 15 minutes, stirring once or twice, until the lamb is tender.
Taste and adjust with salt and black pepper if needed. Serve hot with chopped scallions and lime wedges on the side.