Method

• 1.
  Combine the yeast and milk in a jug and set aside in a warm place for 10 minutes or until frothy.
• 2.
  Sift flour and half the sugar in a stand mixer fitted with the dough hook. Make a well in the centre, add milk mixture and egg yolks, then knead for 5 minutes or until smooth and sticky.

• 3.
  With the motor running, add butter, 1 piece at a time, kneading well after each addition.
• 4.
  Knead for 10 minutes or until butter is completely incorporated. Transfer to a greased bowl, cover and set aside in a warm place for 2 hours or until doubled in size.
• 5.
  Turn out dough onto a lightly floured work surface and shape into a 2.5cm-thick rectangle. Using a 7cm pastry cutter, cut out 9 rounds, re-rolling dough if necessary.
• 6.
  Transfer to a tray, cover with a clean tea towel and set aside in a warm place for a further 30 minutes or until slightly risen.
• 7.
  Half- fill a deep-fryer or large saucepan with sun ower oil and heat to 160°C (a cube of bread will turn golden in 45 seconds when oil is hot enough).
• 8.
  In batches, fry doughnuts, turning, for 5 minutes or until golden and cooked through. Remove with a slotted spoon and drain on paper towel. Repeat with remaining doughnuts.
• 9.
  While still hot, using the tip of a small, sharp knife, pierce a hole in the bottom of each doughnut. Place Nutella in a piping bag tted with a plain nozzle, then use to fill doughnuts.
• 10.
  Combine hazelnuts and remaining 1/3 cup (75g) sugar on a tray. Roll doughnuts in hazelnut sugar to coat, then serve immediately.