Place a bowl with the egg whites and sugar over a pot of simmering water and, stirring constantly, bring the mixture to 60°C until the sugar has fully dissolved. The bowl should not touch the water.

Transfer the egg whites to the mixer bowl, add a pinch of vanillin and beat for at least 10 minutes: first on low speed, then on high.

Add the cornstarch and lemon juice to the thick mixture, quickly fold in with the mixer on low speed.

Transfer the mixture to a piping bag fitted with a tip and pipe nests onto parchment.

Preheat the oven to 160°C, place the meringue inside and lower the temperature to 100°C. Dry for exactly 1.5 hours, then turn off the oven, open the door slightly and leave the meringue until fully cooled.

For the cream, whip the heavy cream with the powdered sugar, add the sour cream and combine.

Fill the meringue with currant jam, top with a dollop of cream and decorate with blueberries.