Mix 2 Tbsp. dark brown sugar and 2 Tbsp. Diamond Crystal or 1 Tbsp. plus ½ tsp. Morton kosher salt in a large bowl to combine. Add one 3-lb. skinless, boneless pork shoulder (Boston butt), cut into 2" cubes, and toss until well coated. Let sit at room temperature 15–30 minutes, or cover and chill up to 12 hours. (No need to bring pork to room temperature before cooking.)

Place a rack in middle of oven and preheat to 350°. Heat 2 Tbsp. vegetable oil in a large ovenproof Dutch oven or other heavy pot over medium-high. Cook half of pork until well browned on 2 sides, 8–12 minutes total (sugar will turn sticky). Transfer to a plate. Repeat with remaining pork and 2 Tbsp. vegetable oil.

Return all of pork to pot. Add 1 large white onion, cut into 1" pieces, 10 scallions, cut into 1" pieces, 8 garlic cloves, thinly sliced, 4 habanero chiles, stems removed, one 3" piece ginger, peeled, thinly sliced, three 3x2" strips orange zest, three 3"-long cinnamon sticks, ⅔ cup cassareep, 1 Tbsp. thyme leaves, 1 tsp. ground allspice, and 1 tsp. freshly ground black pepper, then pour in 6 cups low-sodium beef broth and stir to combine. Bring to a simmer; cover pot. Transfer to oven and braise until pork is fork-tender, 60–80 minutes.

Return pot to stovetop, uncover, and cook, stirring occasionally, over medium-high until sauce is slightly reduced and glazy, 13–17 minutes. Fish out chiles, orange zest, and cinnamon sticks; discard. Taste pepperpot; season with more salt and pepper if needed.

Divide pepperpot among shallow bowls and top with a few microgreens if desired. Serve with warm roti and lime wedges for squeezing over. Do ahead: Pepperpot can be made 3 days ahead; cover and chill. Reheat, covered, over medium heat.