Make the tangzhong

• Whisk the milk and flour in a saucepan until smooth.
• Cook over low heat, stirring constantly, until thickened into a paste.
• Let cool slightly.

Make the donut dough

• Combine the milk, yeast, flour, milk powder, sugar, egg, tangzhong and salt, then knead into a dough.
• Add the first part of the softened butter and knead until absorbed, then knead in the second part until the dough is smooth and elastic.
• Cover and let rise until doubled.

Shape and proof the donuts

• Roll out the dough and cut into 4-inch rounds.
• Place on a lined tray, cover and proof until puffy.

Fry the donuts

• Heat the oil to 170 °C.
• Fry the donuts in batches until golden on both sides.
• Drain on a rack and let cool completely.

Make the crème pâtissière

• Whisk the eggs, corn starch, salt and sugar in a bowl.
• Bring the milk and vanilla to a boil in a nonstick pan.
• Pour the hot milk into the egg mixture while whisking continuously, then return everything to the pan and cook on low heat, stirring constantly, until custard-like.
• Add the butter, mix, pass through a strainer and let cool.

Fill the donuts

• Transfer the crème pâtissière into a piping bag fitted with a Bismarck 230 tip.
• Puncture each donut and fill with custard until it feels heavy.

Make the caramel

• Mix the sugar, water and salt in a nonstick pan and place over low heat.
• Let the sugar dissolve and caramelize without stirring, until deep golden.
• Remove from the heat.

Coat the donuts

• While the caramel is still hot, dip one side of each donut for a thin coating.
• Reheat the caramel if it hardens.
• Let the coating cool and crisp up.

Serve

• Serve and enjoy.