Method

• 1.
  Place milk and yeast in a medium jug and whisk to combine. Add 1 tsp flour and 1 tsp caster sugar and whisk to combine. Stand for 10 minutes or until frothy.
• 2.
  Place remaining flour and caster sugar in a large bowl. Make a well in the centre. Add butter, egg and yeast mixture and stir until well combined. Tip out onto a lightly floured work surface. Gently knead for 3 minutes or until smooth. Return to bowl, cover with a clean tea towel and stand for 1-2 hours until doubled in size.
• 3.
  Line a large baking tray with baking paper. Gently knead dough, then roll out to a 1cm-thick round. Use a 6cm cutter to cut out rounds as close together as possible, then continue re-kneading and re-rolling dough to cut out more rounds until you have 12 in total. Transfer rounds to prepared tray and cover with a clean tea towel. Stand for 1-1 1/2 hours or until twice their original height.
• 4.
  Meanwhile, for raspberry mascarpone, use a fork to mash the raspberries in a large bowl. Add icing sugar and mix until well combined. Stir through mascarpone until well combined, then use a balloon whisk to whisk until firm peaks form.
• 5.
  Spoon into a piping bag fitted with a 1cm round nozzle. Set aside until required. Line a large baking tray with paper towel and another tray with baking paper. Place white sugar in a large bowl.
• 6.
  Place 5cm oil in a large saucepan and heat over medium-high heat until 170°C. Working in batches, carefully lower doughnuts into hot oil using a slotted spoon. Deep-fry, in small batches, for 2-3 minutes, turning frequently until cooked, puffed and golden. Transfer to prepared tray with paper towel to drain briefly before rolling in sugar to coat. Transfer to tray with baking paper. Cool to room temperature.
• 7.
  Using a skewer, pierce a small hole into the side of each doughnut, then pipe in raspberry mascarpone until doughnuts feel heavy and a little of the cream starts to pop out of the pierced hole. Serve with extra raspberries, if using.