In a large mixing bowl, dissolve the yeast in warm water. Sprinkle about a teaspoon of sugar over the mixture and let it sit for around 5 minutes until it becomes foamy. This indicates that the yeast is activated and ready to use.
Stir in the coconut milk, melted butter, egg, remaining sugar, milk powder, and salt. Use a wooden spoon to mix everything until well combined.
Gradually incorporate 3 and 1/2 cups of flour into the mixture, stirring continuously. If needed, add small amounts of the remaining flour until a soft, slightly shaggy dough forms and starts to pull away from the sides of the bowl.
Transfer the dough to a lightly floured surface and knead for about 10-12 minutes until it becomes smooth and elastic. Once properly kneaded, place the dough into a clean, greased bowl, cover it with a kitchen towel or plastic wrap, and let it rise for approximately 1 hour or until it doubles in size.
Once risen, gently punch the dough down to release air. Divide it into 12 equal portions, rolling each into a smooth ball. Arrange them evenly in a lightly greased or parchment-lined 9x13-inch baking pan. Cover them with a clean towel or plastic wrap and allow them to rise again for about 45 minutes.
Preheat the oven to 350°F. Before baking, brush the tops of the rolls with coconut milk. Stir the powdered sugar into the remaining coconut milk until well combined. Once the rolls have risen, pour the sweetened coconut milk mixture into the pan, tilting it slightly to ensure even distribution.
Bake for 22-25 minutes or until the rolls are golden brown on top. Serve warm and enjoy the soft, sweet coconut flavor in every bite.