Place the dough on a flour-covered table on fold it on itself a few times. Cut it into 12 pieces and roll each piece with your hand.
Place the buns on a baking covered baking tray and press them slightly flatter. Use a spoon to press the dough down in the middle and place a spoon of custard.
Let the buns rest for 30 minutes.
Preheat the oven at 210°c
Put aside half of the egg white in a bowl and mix the remaining white with the egg yolk and brush it on the buns (avoid the custard).
Bake the buns for 10-15 minutes, until golden, and set to cool down in room temperature.
Prepare the glazing by mixing icing sugar with the egg white until the texture is thick but still fluid.
Place grated coconut in a soup plate.
Smear, using a spoon, the glazing onto the bun, and roll it in the grated coconut until the glazing is entierely covered.