Method

• 1.
  Combine the yeast, milk and 1 tsp of the sugar in a jug and set aside in a warm place for 10 minutes or until frothy.
• 2.
  Place flour, remaining 70g sugar and cocoa in a stand mixer with the dough hook. Add the milk mixture and egg, then knead for 5 minutes or until smooth and sticky. With the motor running, add butter, 1 piece at a time, kneading well after each addition. Knead for 8-10 minutes until butter is completely incorporated and the dough is soft and elastic (it will be slightly sticky). Transfer to a greased bowl, cover with a damp tea towel and set aside in a warm place for 1 hour 30 minutes- 2 hours until doubled in size.
• 3.
  Turn out dough onto a lightly floured work surface and shape into a 1.5cm-thick rectangle. Using a 5cm pastry cutter, cut out 24 rounds, re-rolling dough if needed. Transfer rounds to a lined tray, cover with a clean tea towel and set aside in a warm place for a further 30 minutes or until risen by half again.
• 4.
  Meanwhile for the hazelnut sugar, mix together the sugar and hazelnut in a large bowl. Set aside.
• 5.
  Half-fill a deep-fryer or large saucepan with oil and heat to 160°C on a deep- frying thermometer. In batches, fry doughnuts, turning, for 4-5 minutes until golden and cooked through. Remove with a slotted spoon and toss straight into the hazelnut sugar.
• 6.
  Place Nutella in a piping bag fitted with a 1cm plain nozzle. Use a small knife to cut a small hole on the side of each doughnut and pipe the Nutella into the doughnuts. Serve immediately.