Step 1

Place a rack in middle of the oven; preheat to 250°. Spread out coconut flakes on a rimmed baking sheet and toast until golden, 10–15 minutes. Let cool.

Step 2

Meanwhile, season beef generously with salt and set aside. Trim top three-quarters from lemongrass stalks and place top portions in a large cast-iron skillet or heavy roasting pan. Peel outer layers from root end and finely grate into a blender. Add shallot, garlic, chiles, ginger, coconut milk, and curry powder; purée until smooth.

Step 3

Arrange short ribs, bone side up, in skillet; pour purée over. Roast until meat is halfway to tender and liquid is reduced by two-thirds (it will look slightly oily and broken, and this is exactly what you want), 3–3½ hours. Turn ribs onto their sides and continue to roast, adding water by ¼-cupfuls if liquid in skillet looks in danger of burning or getting very dark, until meat is fork-tender and liquid is a jammy glaze, 2–2½ hours longer.

Step 4

Toss coconut, cilantro, lime juice, and a pinch of salt in a small bowl. Top short ribs with gremolata and serve with rice.