Mix the milk and yeast together in a small bowl and rest for five minutes.
Combine the flours, sugar, and salt in a large bowl.
Stir in the yeast mixture, softened butter, and beaten egg.
Knead the dough on a floured surface for 10 minutes until smooth.
Place dough in a clean bowl, cover, and prove for 30 minutes.
Preheat the oven to 210°C.
Divide the dough into 12 equal balls and rest for 10 minutes.
Roll each ball into an 8cm circle, fold into a cylinder, and place on trays.
Cover the buns and allow them to rise for 30 minutes.
Glaze with egg, snip the tops, sprinkle with sugar, and bake for 10-12 minutes.