For the doughnuts:
1 large egg, beaten
25g unsalted butter, softened
450g strong white bread flour
½ tsp salt
50g caster sugar, plus extra to serve
2 tsp vanilla extract
1¼ tsp instant dried yeast
For the custard:
65g pistachio nuts
140g white granulated sugar
2 tbsp water
2 egg yolks
2 tbsp corn flour
A pinch of salt
1 tsp vanilla extract
2 tbsp unsalted butter, softened
1. Place all the ingredients for the doughnuts into a bowl. Combine and knead into a soft dough.
2. Cover the bowl with clingfilm and allow to rest in a warm place for about 1 hour or until doubled in size.
3. In the meantime, make the custard. Blend the pistachios in a food processor until finely chopped. Add the sugar and water and whizz until smooth.
4. Place the pistachio mixture in a saucepan with the milk and bring to the boil.
5. As the milk mixture heats, whisk together the egg yolks, sugar, corn flour and salt in a bowl.
6. Once heated, add around 1 cup of the milk into the egg yolk mix whilst whisking briskly and continuously. Once incorporated, add the remaining milk from the saucepan to the egg mixture, whisking continuously.
7. Return the now combined custard mixture to the saucepan and whisk continuously over a medium heat until thickened.
8. Remove from the heat and add the vanilla extract and butter, whisking until the butter has melted and is fully incorporated. Strain the mixture through a sieve and allow to cool to room temperature.
9. Once the dough is ready, turn it out onto a floured surface and cut into 20 equal pieces. Shape into balls and space them, well apart, on a large, greased baking tray.
10. Cover loosely with oiled clingfilm. Leave to rise in a warm place for around 40 minutes, until doubled in size.
11. Heat around 8cm of sunflower oil in a frying pan on a medium heat. Fry the doughnuts for around 1 and a half minutes on each side until golden.
12. Drain the doughnuts on paper towels briefly, before rolling the doughnuts in caster sugar to coat.
13. Place the cooled pistachio custard into a piping bag and inject each doughnut with about a teaspoon of custard. Serve.