So sweet. Pears are a good source of heart-healthy vitamin C.
Preheat oven to 425 degrees. Melt butter in a large ovenproof skillet over medium heat. Place pears, cut side down, in skillet. Increase heat to medium-high and cook, gently shaking pan once or twice, until bottoms begin to lightly caramelize, about 5 minutes. Reduce heat to medium. Carefully turn pears over with tongs. Sprinkle pears with sugar and salt; drizzle 2 tablespoons water into skillet around pears.
Transfer skillet to oven and bake until pears are tender when pierced and sugar has dissolved, about 15 minutes. (Check often; if liquid is getting too dark, add 2 to 3 tablespoons water to skillet and swirl skillet to pull sugar off the bottom.)
Remove skillet from oven and carefully turn pears over with tongs. Add coconut milk; stir around pears with a heatproof spatula to combine milk with cooking liquid. Return to oven and bake, basting once or twice, until sauce has thickened and darkened, about 10 minutes.
Transfer 2 pear halves to each of 4 plates. Place skillet on stovetop over medium heat and cook, whisking constantly, until caramel is slightly thickened and smooth, about 5 minutes. Spoon sauce over pear halves and sprinkle with toasted coconut or almonds, if desired.