Oven preheated to 100C. Line a baking tray with silicone paper. Have a piping bag with round nozzle ready.

In the bowl of the electric mixer place the egg whites and set speed to medium. Mix until the egg whites are firm.

Slowly start adding the caster sugar in whilst still mixing. Once the sugar is combined add the lemon juice, turn up the speed and mix until stiff peaks. (the stiffer the better)

Once the mix is at the right consistency remove half of the meringue mix. In the remaining meringue scatter over the cocoa powder and fold until just combined. Try to retain as much air as possible. Add the un cocoa meringue mix back into the chocolate meringue mix and marble through each other a little.

Spoon into the piping bag and pipe out to 3cm rounds, lifting up at the finish to create the peaks.

Place into the center of the oven and bake for 40-60 minutes depending how you like your meringue. For a meringue with a soft center bake the least, for a firm meringue bake the longest.