This wispy, light, lemony cake (or is it a pudding?) is perfect for spring and simplicity itself to make. The millefeuille – literally 'thousand leaves' in French – refers to the flaky pastry layers, which need to be really crisp and not too thick to provide the proper contrast of textures with the creamy filling. My husband, since his school days, has always referred to this dessert, rather unromantically and for reasons he can't explain, as a flat harry – but I really don't think that this description does any justice to its ethereal quality and exquisite flavour.
This recipe first appeared in Sainsbury’s Magazine (May 1995). Serves 6
Start by unrolling the pastry on to a lightly floured surface. Using a tape measure along the longer edge, mark off 10 inches (25.5 cm). Trim the pastry so that you are left with a shape about 9 x 10 inches (23 x 25.5 cm).
Keep the small strip of pastry for another recipe.
Now roll out the larger piece of pastry to a 12 inch (30 cm) square. Make sure you use a very even, gentle pressure on the rolling pin so that you end up with nice even edges.
Next, grease the baking sheet and then, using the rolling pin, gently transfer the pastry to the baking sheet. Prick the surface of the pastry with a fork and brush it all over with the beaten egg.
Place the baking sheet on a high shelf in the preheated oven and bake for 12-15 minutes – but watch it like a hawk because ovens do vary. What you need is a very crisp finish.
Then to get it really extra-crisp, preheat the grill to its highest setting, sift 1 tablespoon of the icing sugar over the pastry, then literally flash it under the grill – don't take your eyes off it until the sugar caramelises; it will only take a few seconds.
Remove it from under the grill and, using a sharp knife, cut the square into three equal strips.
Then turn them over, sift over the rest of the icing sugar and flash them under the grill once again.
Once it has cooled on a wire rack, the pastry is ready to use and can be stored in a polythene box, each layer separated with greaseproof paper. The pastry is very delicate so handle it carefully, but if any of the strips do happen to break, don't panic – you can use them as bottom or middle layers.
For the lemon crème pâtissière, take a nice roomy bowl and place the egg yolks and whole egg in it. Then, using an electric hand whisk, whisk the eggs together with the sugar until the mixture is pale, thick and creamy (4-5 minutes).
Sift the flour on to the mixture and whisk again until smooth. Finally, add the lemon zest.
Now heat the milk until just coming to the boil, then pour it into the egg mixture and whisk again.
Pour the whole lot back into the saucepan and, stirring continuously with a wooden spoon, heat to a gentle simmer and cook for 2 minutes exactly. It will become quite thick at this stage; if at any time you feel you are 'losing' the sauce, take it off the heat and beat with a wire whisk until smooth again.
Finally, add the lemon juice, a little at a time, and stir in well; the mixture will become liquid again.
Pour the mixture into a bowl, cover the surface with clingfilm, leave until quite cold, then refrigerate until you are ready to serve the millefeuille.
To assemble the millefeuille (do not assemble it more than an hour before it is to be eaten): place one piece of pastry on a board or long plate, cover with half the lemon cream, then place another piece of pastry on top of that.
Spread the rest of the cream over this pastry, then top with the final piece.
Dredge the whole thing with icing sugar and cut into slices with a sharp serrated knife.