Place flour, milk powder, dried active yeast, sugar and raisins in a stand mixer with dough hook attachment. Switch on to blend the ingredients together.
In a jug, mix together the salt, 50g melted butter and egg. Pour into the bowl of the stand mixer with the flour mixture. Switch the machine on and leave for 10 minutes or until the dough is smooth and elastic.
Coat the dough ball lightly in oil and place back into the bowl of the stand mixer bowl. Cover with cling film and let sit in a warm area for 45 to 60 minutes or until double in size.
Lightly grease two large baking trays.
Punch down the dough and divide into 12 equal sized pieces. Roll each piece into a 15cm sausage. Arrange on prepared trays, 5cm apart. Cover with a damp tea towel and let sit in a warm area for 30 to 45 minutes or until puffy.
Meanwhile, preheat oven to 180 C / Gas 4.
Remove the tea towel and bake in the middle of the preheated oven for 12 to 15 minutes or until golden. Transfer to a wire rack to cool.
Stir together the icing sugar, melted butter and just enough water to make a spreadable icing. Spread over the cooled buns. Enjoy immediately or allow to set first.