Method

• 1.
  Place yeast, milk and 1 tsp sugar in a bowl. Set aside for 10 minutes or until frothy. Whisk egg yolks and butter in a bowl.
• 2.
  Combine flour, cocoa and remaining caster sugar in the bowl of an electric mixer fitted with a dough hook. Add egg mixture, then add yeast mixture. Knead on medium speed for 6 minutes or until smooth and elastic. Place in a greased bowl and cover with plastic wrap. Set aside in a warm place for 1 hour or until doubled in size.
• 3.
  Knock back dough and place between two sheets of baking paper. Roll out to an even thickness of 5mm. Using a 9cm cutter, cut out 6 rounds, then using a 3.5cm cutter, make a hole in the centre of each round. Place on a baking paper-lined baking tray. Cover with a clean tea towel. Set aside for 20 minutes or until slightly risen.
• 4.
  Half-fill a saucepan or deep-fryer with oil and heat to 170ºC (a cube of bread will turn golden in 50 seconds when oil is hot enough). In batches, deep-fry doughnuts, turning halfway, for 5 minutes or until fluffy and cooked through. Remove using a slotted spoon and drain on paper towel.
• 5.
  For the glaze, whisk all ingredients in a bowl until smooth. Dip one face of doughnuts in glaze, then place, glazed-side up, on a wire rack. Scatter with salt, if desired. Serve warm.