3 Tbs. unsalted butter
1 Tbs. minced fresh ginger
1 cup jasmine rice
3/4 cup well-shaken unsweetened coconut milk
Kosher salt
1/3 cup dark rum
3 Tbs. packed dark brown sugar
2 medium limes, finely grated to yield 1 tsp. zest and squeezed to yield 1/4 cup juice
2 Tbs. vegetable oil; more as needed
1 tsp. ground allspice
1/8 tsp. ground cayenne
Freshly ground black pepper
1 1- to 1-1/4-lb. pork tenderloin, cut into 1-inch cubes
1 medium red bell pepper, cut into 1-inch squares
1 red onion, cut into 1-inch pieces
Lime wedges for serving (optional)
Melt 1 Tbs. of the butter in a 2-quart saucepan over medium heat. Add the ginger and cook, stirring, until fragrant, about 1 minute. Add the rice and stir until well coated. Add the coconut milk, 1-1/2 cups water, and 3/4 tsp. salt; bring to a simmer. Reduce the heat to low, cover, and cook until the liquid is absorbed, about 15 minutes.
Fluff with a fork, cover, and set aside. Meanwhile, combine the rum, brown sugar, 2 Tbs. of the lime juice, and the remaining 2 Tbs. butter in a 1-quart saucepan. Bring to a simmer over medium heat and cook until syrupy, about 5 minutes. Stir in 1/8 tsp. salt and remove from the heat.
In a medium bowl, combine the remaining 2 Tbs. lime juice with the oil, allspice, cayenne, 1-1/2 tsp. salt, and 1/2 tsp. black pepper. Add the pork and toss to coat. Thread the pork, bell pepper, and onions onto four 12-inch metal skewers, alternating the meat and vegetables.
Prepare a medium-high (400°F) gas or charcoal grill fire or heat a large grill pan over medium-high heat. Oil the grate or pan. Grill the skewers until seared on all sides, about 4 minutes total. Brush the skewers with the glaze and grill, turning occasionally, until the pork is browned on the outside but still slightly pink in the center, 2 to 4 minutes more.
Add the zest to the rice and fluff. Brush the skewers with any additional glaze and serve with the rice and lime wedges, if you like.