Line a high-sided 20 x 30cm baking tin with baking parchment. To make the tangzhong, put the flour, milk and 30ml water in a small saucepan. Whisk over a medium heat until it becomes a thick paste, then set aside until it is at room temperature.

Pour the milk into a saucepan and set over a low heat until just warm. Alternatively, warm in the microwave in 10-second blasts, but be careful not to boil it. Stir in the yeast to fully combine. Mix the flour, sugar and 1 tsp fine sea salt in the bowl of a stand mixer with a dough hook attachment. With the mixer running, add the egg, tangzhong and milk mixture. Knead for 2 mins, then add the butter, bit by bit. Continue to knead for a further 7-8 mins until soft, elastic and slightly sticky. Form into a ball and put into a lightly oiled clean bowl. Cover and set aside to rise for around 2 hrs until doubled in size. Will keep chilled overnight. Bring up to room temperature, then leave to rise until doubled before continuing.

Lightly dust a clean work surface with flour and knock back the dough for 10 seconds. Divide into eight pieces (around 85g each), and form into small balls. Put the balls in the prepared tin and cover. Set aside to rise for 1 hr or until doubled in size.

Heat the oven to 200C/180C fan/gas 6. Generously brush some milk over the buns to glaze and bake for 20-25 mins until golden and risen. Leave to cool in the tin for 15-20 mins before transferring to a wire rack to cool completely. Will keep in an airtight container for three days or frozen for two months.