Iced Donuts

Preheat the oven to 400u0b0F. Line 2 baking pans with parchment paper.
Heat milk in a small saucepan until lukewarm. Whisk in yeast and half the sugar. Set aside for 10 mins or until frothy.
Sift flour into a large bowl. Stir in remaining sugar. Add yeast mixture, butter, eggs and egg white; mix to a soft dough. Turn out onto a lightly floured surface.
Knead dough for 5 mins, or until smooth and elastic. Place dough in a clean bowl; cover with plastic wrap, then a tea-towel. Let stand in a warm place for 45 mins, or until doubled in size.
Punch down dough, then knead for 3 mins. Cut dough into 2 equal pieces. Knead each piece for 5 mins. Roll out each piece to 1/2-inch thickness. Using a floured 3-inch round cutter, cut dough into discs. Using a floured 1 1/2-inch round cutter, cut out center of each disc. Place donuts on prepared pans. Knead leftover dough then roll out to 1/2-inch thickness. Using cutters, cut out more donuts to make 26 in total.
Bake one pan at a time for 8 mins, or until risen and browned. Wrap in a clean tea-towel to cool.
Meanwhile, for the icing, sift powdered sugar into a medium heatproof bowl. Stir in milk and vanilla to form a thick paste. Add a few drops of food color, if desired. Place bowl over a saucepan of simmering water (don't let bottom of bowl touch the water). Stir until runny and glossy.
Dip top of each donut into icing. Using a knife, quickly remove excess icing. Press gently into chocolate sprinkles to coat. Let stand until icing is set.