Step 1

To make the dough, put the flour, sugar, salt, yeast and lemon zest into a large bowl and mix together. Put the milk and butter into a small pan and heat gently until the butter has melted, then set aside to cool to lukewarm. Add the milk mixture and 1 egg to the flour mixture, gradually, and mix to form a shaggy dough (you may not need all of the liquid). Knead until the dough is smooth and elastic (10-15 minutes). Put the dough into an oiled bowl, cover with clingfilm and allow to rise for about an hour, or until doubled in size.

Step 2

To make the filling put the butter and chocolate into a small, heatproof bowl set over a pan of simmering water, heating until fully melted. Remove from the heat and use a small whisk to mix in the icing sugar and cocoa powder. Set aside until thickened to a spreadable consistency.

Step 3

Put the dough on a lightly floured worksurface and roll out into a rectangle, roughly 40 x 60cm. Spread the filling over half of the dough and top with the pistachios and sea salt flakes. Fold the uncovered dough over the filling and gently press together. Using a sharp knife or a pizza cutter, cut into thin strips between 2 and 2.5cm thick. Twist each strand of dough a few times then, gripping one end between your thumb and forefingers, coil the dough around the fingers to form a bun shape, finishing by folding the end of the dough over and under (look at p46 to remind yourself of the final shape).

Step 4

Put each bun onto a baking paper-lined tray, leaving 5cm of space between each bun. Cover the tray lightly with a piece of clingfilm and set aside until risen and puffy (about 45 minutes – 1 hour).

Step 5

Heat the oven to 190C/fan 170C/gas When ready to bake, brush the buns with beaten egg. Bake for 20 minutes or until golden brown.

Step 6

Make the glaze by boiling the sugar, together with 75ml water, for a couple of minutes. Remove from the heat and add the vanilla. While the buns are fresh from the oven, brush liberally with the glaze, sprinkling with a few extra chopped pistachios. Store in a sealed container for up to three days.