Lemon Mille-feuille

Instructions

Heat the oven to 400 °F (200 °C). Unroll the puff pastry on a lightly floured surface and trim it to a rectangle of about 23 x 25.5 cm. Roll the larger piece out to a 30 cm square, pressing gently and evenly with the rolling pin so the edges stay neat.

Grease a baking sheet and use the rolling pin to lift the pastry onto it. Prick the surface with a fork and brush all over with the beaten egg. Bake on a high shelf for 12 to 15 minutes, until crisp and golden.

For extra crispness, turn the oven to its highest setting, sift 1 teaspoon of the icing sugar over the pastry and flash it under the grill. Take it out and cut the square into three equal strips with a sharp knife.

Turn the strips over, sift the remaining icing sugar over them and flash them under the grill again. Cool on a wire rack. If you are not assembling right away, store them in a plastic box with greaseproof paper between the layers.

Put the egg yolks and whole egg in a roomy bowl. Whip them with the castor sugar using an electric mixer for 4 to 5 minutes, adding the milk as you go, until the mixture is pale, thick and creamy.

Sift the flour over the mixture and whisk again until smooth. Stir in the lemon zest and juice to finish the filling.

Set one pastry strip on a plate and cover it with half of the lemon filling. Lay the second strip on top and spread over the rest of the filling. Finish with the last pastry strip.