She says this quantity will serve 8-10, but with the chocolate filling it is very rich and will serve more.
2
Mix cornflour and sugar. Put egg whites in mixer bowl with pinch of salt.
3
Whisk at low speed until frothy, then increase speed and whisk until mixture is makes stiff but glossy peaks. Start adding sugar/cornflour a bit at a time, beating till stiff after each addition. When all mixture had been added, beat in vinegar and vanilla.
4
Spoon or pipe into 2 8" circles on silicon paper lined baking trays. Have oven heated to 300F,150C. Turn down to 275F, 140C. Put cakes in and bake for 45 min to 1 hour, swapping over position halfway through. They are ready when top is firm and crisp to touch.
5
Filling: Melt some chocolate and mix with a beaten parev whip. Should be quite dark brown and taste definitely of chocolate.
6
When meringues are cool sandwich together with filling. Can be served from fridge or freezer.