In a small bowl, mix warm milk with a pinch of sugar and sprinkle in active dry yeast. Let it sit until bubbly.

In a large mixing bowl, combine bread flour, sugar, and salt, creating a well in the center. Pour in the yeast mixture, melted butter, and beaten egg. Mix until combined, then knead for 15-20 minutes until smooth and elastic.

Place the kneaded dough into a greased bowl, coating it in oil. Cover and let it rise in a warm area for about 1 hour until doubled in size.

In a medium bowl, mix shredded coconut, melted butter, dry milk powder, sugar, all-purpose flour, and a pinch of salt until crumbly.

Deflate the dough and turn it out onto a floured surface. Divide into 12 pieces, shape into balls, flatten into discs, and place coconut filling in the center. Seal each bun.

Cover shaped buns and let them rise for an additional 30-40 minutes in a warm area. Preheat oven to 350°F.

Combine melted unsalted butter, all-purpose flour, and confectioner's sugar until smooth. Whisk together egg and heavy cream or milk for the egg wash.

Brush the buns with egg wash, pipe topping over them, and sprinkle with sesame seeds if desired. Bake for about 20 minutes until golden brown.

Allow to cool slightly before serving.