Warm the milk to blood temperature, about 44C.

Pour the milk into the bowl of your mixer. Add the yeast and leave to bubble for a few minutes before adding the sugar, egg, egg yolk and melted butter. Mix well.

Next add the flour and mix slowly till well combined. Now you can use the dough hook to knead it for a good 6-8 minutes until it forms a smooth but sticky dough. This can all be done by hand too with a kneading time of 8-10 minutes.

Transfer the dough to a well oiled bowl and cover with cling film (a shower cap works really well too) and a tea towel. Keep in a warm place till doubled in size, this can take 60-90 minutes.

Meanwhile finely chop the rhubarb into tiny dice. Stir the rhubarb with the sugar and set aside.

Flour your worktop and once the dough is ready roll it out into a 23cm by 35cm ( 9-inch by 14-inch) rectangle. Spread the soft butter over the dough then scatter with the sugared rhubarb leaving a border around the edges.

Starting at the 23cm side, roll the dough neatly and confidently into swiss roll shape ending seam side down. Use a serrated knife to cut nine swirls of 2.5cm (1 inch) each. Line a 23cm round tin with parchment and arrange the buns in the tin. Leave to rest for 30 minutes. Preheat the oven to 180C. Bake for 25 minutes till just turning golden brown.

Meanwhile, mix the icing sugar, custard powder, vanilla and 2tbsp milk together till it forms a smooth paste. Keep adding milk till it becomes like very thick pouring cream.

Leave buns to cool for 10 minutes before drizzling with the custard glaze.