Beat the egg whites and lemon juice with the whisks of the hand mixer until stiff. Slowly pour in the sugar and continue beating until the sugar has dissolved and a shiny mass has formed
Pour half of the meringue mixture into a piping bag with a perforated spout. Spray small dots onto a baking tray covered with baking paper. Fold the cocoa into the remaining meringue and squirt it onto the baking tray in small tuffs
Bake the tray on the lower rail in a preheated oven (electric cooker: 125 °C/ convection oven: 100 °C/ gas: not suitable) for approx. 1 hour. Reduce temperature (electric oven: 100 °C/ convection oven: 75 °C) and bake for approx. 1 further hour. Then switch off the oven and let it cool down in the closed oven with residual heat. Dust the cocoa meringue with cocoa before serving
Waiting time approx. 1 hour