Make the Tangzhong: In a small pot, whisk together the flour and milk. Cook over medium heat, stirring constantly until a thick paste forms. Chill in the fridge for 5 minutes.

Prepare the Dough: In a large bowl, combine flour, sugar, salt, milk powder, yeast, egg, egg yolk, tangzhong, and warm milk. Mix until a dough forms, then add butter and knead for 15 minutes until smooth and elastic.

Place dough in a greased bowl, cover, and let rise in a warm place for 1–2 hours or until doubled in size.

Shape the Doughnuts: Divide risen dough into 80g portions, shape each into a ball, and slightly flatten. Place each ball on a square of baking paper. Cover loosely and let rest for 45 minutes until slightly puffy.

Fry the Doughnuts: Heat oil to 160°C (320°F). Fry doughnuts in batches until golden brown on both sides. Drain on a wire rack.

While still warm, coat each doughnut in sugar and let cool.

Fill with Pistachio: Fill a piping bag fitted with a round tip with pistachio spread. Poke a hole in each doughnut and pipe in the filling generously.