Method

• 1.
  Preheat oven to 200°C. Line 2 baking trays with baking paper. Place pastry on trays and top with a sheet of baking paper and another baking tray. Bake, turning trays around once so colour is even, for 30 minutes or until golden. Transfer to a wire rack to cool.
• 2.
  Meanwhile, place cream, sugar, vanilla and half the lemon zest in a saucepan over medium heat. Bring to a simmer, stirring regularly to dissolve sugar. Place 2 tbs hot cream mixture in a bowl, add custard powder and mix until smooth. Return to the hot cream and stir to combine. Remove from the heat. Squeeze water from gelatine and stir into cream mixture until combined. Set aside to infuse for 1 hour at room temperature.
• 3.
  Strain cream mixture through a fine sieve into a bowl, cover surface directly with plastic wrap and chill for at least 1 hour 30 minutes to set to a thick, dolloping consistency.
• 4.
  Grease a 20cm square cake pan and line with long sheets of baking paper, allowing paper to hang over the sides so that you can use the paper to remove the slice from the pan. Using a serrated knife, trim pastry sheets to fit snugly in the pan, then place 1 pastry sheet in the base.
• 5.
  Place extra 1 1/2 cups (375ml) cream in the bowl of a stand mixer with the whisk attachment. Whisk for 1 minute or until stiff peaks form. Whisk set cream mixture to loosen slightly, then add the set cream mixture to the whipped cream and whisk until smooth and soft peaks form, being careful not to over whisk. Spoon over pastry in prepared pan, spreading it to the edges, then press remaining pastry sheet on top. Chill for 3 hours or until set.
• 6.
  Whisk icing sugar, remaining lemon zest, lemon juice and enough hot water (about 2 tsp) in a bowl to form a smooth icing, and spread over top sheet of pastry. Chill for 30 minutes or until set then slice into 10 pieces to serve.