Beat the egg whites, 1 pinch of salt and lemon juice with the whisk of the hand mixer until stiff, finally add sugar. Continue beating until a smooth, firm, shiny mixture is obtained. Pour the meringue mixture into a piping bag with perforated spout (1-2 cm Ø)
Line a baking tray with baking paper, squirt 12 oval portions (each approx. 6 cm long) onto the baking tray. Use a teaspoon to press a small depression into each portion. Bake in the preheated oven (electric cooker: 100 °C/recirculating air + gas: not suitable) for approx. 2 1/2 hours on the lower rail of the oven, sliding 1 baking tray over it. Switch off the oven and let the meringue cool down overnight
Defrost blueberries in a bowl for about 30 minutes. Whip the cream with the whisk of the hand mixer until stiff, fold in the blueberries. dust meringue shells lightly with cocoa, spread cream on meringue shells
waiting time approx. 12 1/2 hours