Prepare the dough the day before baking. Whisk the eggs and milk together in a jug. Put the flour, cocoa powder, white and milk chocolate chunks, yeast, sugar and a pinch of salt in the bowl of a stand mixer fitted with a dough hook.

With the motor running on a medium speed, slowly pour the wet ingredients into the dry and mix until everything is incorporated and comes together into a soft dough, about 2-3 mins. Gradually add the butter, and slowly increase the speed, kneading for 8-10 mins until the dough comes away from the side of the bowl and clings to the hook. Scrape the dough off the hook (it will be very sticky at this point), cover and chill overnight.

Tip the dough onto a lightly floured work surface. Divide into nine equal pieces, about 100g each. Knead each piece slightly and pull the dough in on itself to create a ball. Arrange the dough balls on a baking tray lined with baking parchment, leaving some room between each. Cover and leave to prove in a warm place for 2 hrs, or until almost doubled in size.

Heat the oven to 200C/180C fan/gas 6. For the topping, combine the flour, sugar and 3 tbsp water, adding the water 1 tbsp at a time until you have a thick paste. Spoon into a piping bag fitted with a small nozzle and pipe crosses onto the buns. Bake for 20 mins until risen. Meanwhile, heat the apricot jam in a small pan over a low heat to loosen, then brush over the warm buns. Leave to cool before serving.