Preheat the oven to 150°C.
Draw a 20cm circle on three pieces of baking parchment and place on trays.
Beat egg whites with salt until soft peaks form, then gradually whisk in the sugar.
Fold in vinegar and cornflour and whisk at high speed until glossy stiff peaks form.
Divide the meringue between the three circles.
Bake for 60 to 75 minutes until a crisp crust forms, then cool slowly in the oven with the door open.
Whip cream and icing sugar to soft peaks and stir in passion fruit flesh.
Melt lemon zest, juice, sugar, and butter in a bowl over simmering water.
Whisk whole eggs and yolk together, then stir into the lemon mixture.
Heat the curd over simmering water for 10 to 13 minutes until thick enough to coat a spoon.
Stack meringue discs with layers of passion fruit cream and drizzled lemon curd.
Decorate the top with remaining curd and lemon zest.