Lemon meringue tiramisu

Method

• Step 1
  Place egg yolks in a heat-proof bowl with sugar, zest and juice. Place bowl over a saucepan of simmering water and whisk for approximately five minutes until pale and creamy and doubled in size. Rub some of the mixture between your finger and thumb to ensure the sugar is completely dissolved. Remove from heat and allow to cool, then whisk in mascarpone. Fold through whipped cream.
• Step 2
  To make lemon syrup, heat sugar and lemon juice in a saucepan and simmer for 1-2 minutes until sugar is dissolved and mixture has thickened. Pour into a shallow dish.
• Step 3
  To assemble, dip savoiardi biscuits in lemon syrup and place in a single layer in the base of a casserole dish (I used a 28cm x 20cm dish). Spoon over half the mascarpone cream mixture and spread into an even layer. Dollop over the lemon curd, if using, and spread out. Add a second layer of syrup-dipped biscuits then the remaining mascarpone mixture. Finish with a third layer of syrup dipped biscuits. Refrigerate for at least 4 hours or overnight.
• Step 4
  To make meringue, place sugar in a saucepan with 1/4 cup + 1 tbsp water. Bring to the boil, stirring, until sugar has melted. Continue simmering until it reaches 115C on a sugar thermometer - this will take about 8-10 minutes. In a stand mixer or using hand-held beaters, beat egg whites and lemon juice until thick. With the motor running on medium speed, pour the hot sugar syrup in a slow steady stream, beating continuously. Once all the syrup has been added, continue beating until meringue is thick and glossy.
• Step 5
  Spoon meringue into a large piping bag with an open star piping tip. Pipe meringue onto the top layer of the tiramisu, being sure to fill all of the gaps. If you have a kitchen blow torch, gently torch the meringue just prior to serving.