• Grease and line a 23cm square cake tin.
• Place the yeast, milk and sugar in a jug, mix until the sugar has dissolved then set aside for about 10 minutes until it froths.
• In the bowl of an electric mixer, place the sifted flour and butter. Using the dough hook, mix until it resembles fine breadcrumbs. Add the sugar and mix. Pour the egg into the bowl and mix it then then finally add the yeast mixture. Knead the mixture using the dough hook until it comes away from the sides of the bowl.
• Turn the dough out onto a floured surface and knead until smooth.
• Halve the dough and shape one half into a ball then place in a lightly oiled bowl.
• Knead the cocoa into the other portion of dough, form it into a ball and place it in a lightly oiled bowl. Cover the bowls and leave the dough to rise for 1 hour.
• When the doughs have doubled in size, working with one at a time, turn them out onto a floured surface. Knead the chocolate chips into the chocolate dough then separate the dough into 8 round portions and set aside.
• Knead the sultanas into the white dough and divide it into 8 round portions.
• Arrange the dough in the tin in a checkerboard pattern, cover and set aside for about 30 minutes until they have slightly risen.
• Pre-heat the oven to 180C(360F) fan-forced.
• The original recipe uses icing after the buns have been cooked and cooled to form the crosses. I wanted a more traditional baked-on cross on mine so I mixed together flour and water and piped it on before the buns went in the oven.
• Bake the buns for 10 minutes then reduce the oven temperature to 160C and bake for a further 25 minutes.
• When cooked, leave them in the tin for 5 minutes before turning onto a wire rack to cool.
• Serve the buns warm with butter.

Enjoy!