Vanilla Mille-Feuille with Feathered Icing

Cream. in a pan off the heat, beat the yolks with the sugar, cornflour and salt until smooth, then gradually beat in the milk. Cook over medium heat, whisking, until it thickens and bubbles for 1 min; it will pass 85 °C. Sieve, whisk in the butter and vanilla, cover the surface and chill at least 3 h.

Roll. heat the oven to 200 °C (180 °C fan). Roll the pastry on a floured worktop to a 30 x 40 cm sheet, 3 mm thick. Lay it on a lined tray, prick all over with a fork and chill 15 min.

Bake flat. cover with baking paper and the second tray to stop it rising, and bake 20 min. Remove the top tray and paper and bake 10-15 min more until deep golden and crisp right through. Cool on the rack, then trim and cut into 3 equal strips about 12 x 30 cm. The tray on top keeps the pastry thin, even and very crisp.

Ice. choose the flattest strip for the top. Melt the chocolate and spoon it into the small bag. Mix the icing sugar with enough water to make a thick, spreadable icing, spread it over the top strip and at once pipe thin chocolate lines lengthwise 1.5 cm apart. Drag the cocktail stick across the lines, alternating direction every 2 cm, to feather. Set 30 min. Feather straight away, while the icing is still wet.

Lighten. whip the cold cream to firm peaks. Whisk the chilled pastry cream smooth and fold in the whipped cream. Spoon into the piping bag.

Build. pipe rows of cream over the first strip, cover with the second strip and press lightly, pipe a second layer and top with the iced strip. Chill 1 h, then cut into 8 slices with the serrated knife using a gentle sawing motion.