Chocolate croissants

Whisk the bread flour, pastry flour, yeast and sugar in the bowl of a stand mixer, then add the kosher salt, soft butter and milk.

Knead 1 to 2 minutes until soft, tacky, slightly lumpy, homogenous and dough-like.

Stretch into a taut ball, drop into an oiled bowl and proof at room temperature 1 to 2 hours or until grown by 50 to 100%.

Turn out onto a well-floured surface and roll, stretch and tease into an 8 by 12 inch rectangle about half an inch thick; cover in plastic wrap and refrigerate.

Lightly flour the unsalted butter and pound, fold and roll it repeatedly until it is flexible enough to fold without breaking, then shape it into a rectangle about half the size of the lean dough.

Wrap the butter square and refrigerate no more than 15 minutes.

Brush excess flour off the dough, lay the butter square on one side, close it like a book and pinch all edges shut.

Press dimples into the dough, roll out gently to a rectangle about 10 by 16 inches, popping any air bubbles, and fold into thirds.

Wrap and refrigerate 30 minutes between turns, and repeat the roll and fold twice more.

Refrigerate at least one night and up to three.

Press and roll the dough to a rectangle about 10 by 16 inches and about a quarter inch thick, then trim to 10 by 12 inches.

Mark every four inches and cut into isosceles triangles four inches wide at the base; press and smear the tip into the surface and stretch each triangle longer and wider.

Notch the base of each triangle and roll up around batons of chocolate.

Proof at room temperature on parchment-lined baking sheets under oiled plastic wrap.

Whisk the egg yolk, salt, sugar and heavy cream until homogenous for the egg wash.

Brush the pastries with egg wash, keeping it off the cut sides, which impedes the rise.

Bake at 400 degrees Fahrenheit for 10 minutes, then at 375 for a further 15 to 20 minutes.

Move to a wire rack immediately and cool until no longer piping hot.

Variation, pain au chocolat: trim the dough to 3 by 6 inch rectangles, place two batons at one end, roll until covered, add two more batons and roll into a log, pressing to seal.

Variation: cover and proof at room temperature 1 to 2 hours until grown by about 50%, egg wash off the cut sides, then bake at 400 degrees Fahrenheit for 10 minutes and 375 for a further 15 to 20, until deeply brown and 200 to 210 degrees at the thickest point.