Chocolate orange Chelsea buns

1. Sift the flour into a bowl, then stir in the yeast, caster sugar, salt and half the orange zest.

2. Mix the melted butter, warm milk and egg in a jug. Make a well in the centre of the flour, then pour the liquid into the bowl and bring the mixture together with a spatula. Turn the dough out onto a lightly floured surface and knead by hand for 10 minutes, until the dough is smooth. Return the dough to a clean, lightly oiled bowl, cover with a piece of oiled clingfilm or a clean damp tea towel and leave in a warm place for an hour until the dough has doubled in size. Grease and line a 20cm x 30cm x 5cm deep baking tin with baking parchment. Knead the dough again for two minutes on a lightly floured surface, then roll out to a rectangle about 35cm x 45cm. Spread the soft butter evenly over the dough, leaving a 1cm border at one of the long ends. Mix the sugar, cinnamon, sultanas, chocolate chips and remaining orange zest in a small bowl, then scatter evenly over the dough. 3. Dampen the long end of the dough with a little water then roll up, pinching the seam closed. Cut the roll into 12 even slices. Place the slices cut side up into the prepared tin, spaced about 1.5cm apart. Cover the tin with oiled clingfilm or a damp tea towel and leave to prove for about 40 minutes, until doubled in size. Preheat the oven to 180°C/160°C fan/gas mark 4.

4. Bake the Chelsea buns for about 25 minutes, until golden. Allow the buns to cool slightly in the tin before transferring to a cooling rack.

5. Warm the apricot jam in a small pan with the boiling water, then brush over the top and sides of the Chelsea buns. To make the glaze icing, sieve the icing sugar into a bowl and stir in the orange juice to make a smooth icing.

6. Drizzle the chocolate over the buns, let it set slightly, then drizzle over the icing.