Pain au chocolat

Whisk the flour, sugar and salt together in a large bowl until evenly combined. Combine the yeast and milk. Create a well in the centre of the dry ingredients and pour in the milk mixture. Using a tightly cupped hand, stir, fold and briefly knead the mixture in the bowl to create a relatively smooth dough, drawing in all the flour. It doesn’t matter if it’s a little rough at this stage – it’s more important that you don’t overwork the gluten, which will make it difficult to roll out later. Shape into a ball and put in a lightly oiled, large lidded container. Leave at room temperature for 30 mins to activate the yeast, before chilling for at least 4 hrs or ideally overnight.

Meanwhile, arrange the butter slices in a square shape in the centre of a large sheet of baking paper. Fold the paper over the butter so it's fully encased, then lightly bash with a rolling pin to make it more pliable, forming it into a smooth, sharp-edged 18cm square. Wrap in the paper and chill in the fridge alongside the dough for at least 4 hrs or ideally overnight.

The next day, remove the butter and dough from the fridge. Put the dough on a lightly floured worksurface. Using a serrated knife, cut a cross into the centre of the dough, going halfway through and creating four sections. Gently pull each quarter up and out, away from the centre, and roll into roughly 5mm-thick flaps, creating a cross shape that is even in thickness with an 18-20cm square centre. Unwrap the butter and put it in the centre of the cross, then fold over the flaps to fully encase it, dusting off any excess flour as you go. You should now have a square that's roughly 20cm in size. Use a rolling pin to make small ridges down the length of the dough, then gently roll in short, sharp motions to create a smooth, sharp-sided 40cm x 70cm rectangle. The aim is to evenly thin the butter within the dough, rather than pushing it to one end. This will create an even lamination.

Brush off the excess flour (this is important, as it will inhibit the layers from bonding), then fold the shortest edge of the dough (furthest away from you) into the centre. Fold the bottom edge up to meet your initial fold in the middle so the two meet but are not overlapping. Finally, fold over the short edge that's closest to you, so the dough looks like a rectangular closed book. Gently press the four edges down using a rolling pin, then wrap in baking paper, transfer to a baking tray and chill for 30 mins-1 hr, depending on how warm your kitchen is (you want the dough to feel cool and firm, but not hard).

Put the dough on a lightly floured worksurface with the seam facing to the right. Roll the dough out as before, this time to a 30cm x 60cm rectangle. Repeat step four until you have completed a total of three rolls and folds, chilling for 30 mins-1 hr between each. If the dough is difficult to roll and keeps bouncing back, chill it for longer to allow the gluten to relax. There should be no streaks of butter visible through the dough by the final roll and fold.

After the final chill and third rolling and folding process, roll the dough out to a 25cm x 60cm rectangle that's roughly 3-5mm thick. Using a sharp knife in a downward motion, trim the edges of the dough to straighten, creating a 24cm x 58cm rectangle. Cut into 12 8cm x 14cm rectangles, being careful not to drag the knife through the dough – this will damage the layers of lamination. Working with one dough rectangle at a time, brush off the excess flour and put a chocolate baton on one end. Roll the dough over the baton, then add another baton and roll up like a swiss roll. Arrange seam-side down on a baking tray lined with baking paper (you may need to use two trays), then repeat with the remaining rectangles, leaving a 5cm gap between each one. If the seams start to unfold, gently brush with a little water to help keep them together. Chill for at least 2 hrs or ideally overnight.

When you’re ready to bake, take the pain au chocolat out of the fridge and prove at room temperature for approximately 2 hrs-2 hrs 30 mins until they have started to puff up and have a gentle wobble when you jiggle the tray. Whisk the egg yolk, double cream or milk and a pinch of sea salt together, and gently brush this over the tops of the pastries. Chill for 20 mins to help set the shape.

Heat the oven to 230C/210C fan/gas 8. Bake on the middle shelf of the oven for 10 mins, then reduce the temperature to 190C/170C fan/gas 5 and bake for a further 10-15 mins or until deep golden and they feel light. Cover with foil if they start to turn too dark. Cool on a wire rack until just warm, then serve.