Place the egg whites, caster sugar, cornflour and lemon juice in a bowl. Beat the egg whites with an electric mixer until you have a firm, smooth meringue. Fill a piping bag fitted with a plain tip with the meringue. Poach on a baking tray lined with baking paper.
Cuire la meringue dans un four préchauffé à 95°C, pendant 2 heures environ. Eteindre le four et laisser la meringue encore 30 minutes dans le four éteint.
Whip the cold cream with the mascarpone using an electric mixer. Gradually add the caster sugar. Fill a piping bag fitted with a plain tip with this whipped cream.
Assembly
Turn over the cold meringue. Poach the whipped cream.