Instructions

1. 1
   Preheat the oven to 400 °F (200 °C).
2. 2
   Unroll the pastry on a lightly floured surface.
3. 3
   Trim the pastry so that you are left with a rectangle approximately 23 x 25.5 cm.
4. 4
   Roll out the larger piece of pastry to a 30 cm square, making sure you use a very even, gentle pressure on the rolling pin so that you end up with nice even edges.
5. 5
   Grease a baking sheet and use the rolling pin to transfer the pastry to the baking sheet.
6. 6
   Prick the surface of the pastry with a fork. Brush the pastry all over with the beaten egg.
7. 7
   Place the baking sheet on a high shelf in the oven and bake for 12–15 minutes until crisp and golden.
8. 8
   To get it extra crisp, heat the oven to its highest setting, sift 1 teaspoon of the icing sugar all over the pastry, and flash it under the grill.
9. 9
   Remove from the grill and, using a sharp knife, cut the square into three equal strips.
10. 10
    Turn the strips over, sift the rest of the icing sugar over them, and then flash them under the grill again.
11. 11
    Cool on a wire rack, then store in a polythene box, each layer separated with greaseproof paper.
12. 12
    Place the egg yolks and whole egg into a roomy bowl.
13. 13
    Use an electric mixer to whip the eggs together with the castor sugar until the mixture is pale, thick and creamy (4–5 minutes). Add the milk as you mix.
14. 14
    Sift the flour onto the mixture and whisk again until smooth.
15. 15
    Add the lemon zest and juice.
16. 16
    Place a pastry strip on the plate, and cover with half the lemon filling.
17. 17
    Put the second pastry strip on the creme, and cover with the remaining lemon filling.
18. 18
    Finally, top with the final pastry strip.