Method

• 1.
  Preheat oven to 180°C and grease two 20cm cake pans.
• 2.
  Sieve cornflour, custard powder, cream of tartar and bicarb into a bowl. Set aside.
• 3.
  Place eggwhites and a pinch of salt in a stand mixer fitted with the whisk attachment and whisk until soft peaks form. Gradually add sugar, 1 tbs at a time, and whisk for 10 minutes or until sugar is dissolved. Add egg yolks, 1 at a time, whisking constantly, until combined.
• 4.
  Using a spatula, gently fold in cornflour mixture. Divide batter evenly between prepared pans, smoothing tops with spatula. Lightly tap pans on a benchtop to release any air bubbles.
• 5.
  Bake for 20-25 minutes or until a skewer inserted into the centre comes out clean. Cool in pans for 10 minutes, then remove and transfer to a wire rack to cool completely.
• 6.
  Meanwhile, for the lemon filling, place ¾ cup (180ml) water, sugar, cornflour, a pinch of salt, egg yolk and lemon juice in bowl and whisk to combine. Pour into a medium saucepan over medium-low heat and cook, stirring constantly, for 4-5 minutes or until thickened. Remove from heat and stir in lemon zest and butter. Set aside to cool completely.

• 7.
  For the lemon icing, in a bowl, combine icing sugar with enough lemon juice to make a soft icing.
• 8.
  To assemble, place 1 cake on a serving plate, spread with lemon filling and cream, and top with remaining cake. Drizzle lemon icing over top, allowing some to drip down sides, and sprinkle with pared zest.