Pre-heat the oven to 100ºC/80ºC fan.

Finely grate the dark chocolate (50g).

Put your 4 egg whites into a large bowl and whisk on a low speed until foamy. Once foamy, increase the speed to medium until the egg whites form stiff peaks.

Add the caster sugar (200g) a tablespoon at a time and whisk at a medium speed until combined. Continue to whisk until your meringue is stiff (if you remove the whisk it'll stand up in a peak).

Sift the cocoa powder (1 tbsp), and then add the cocoa powder and grated chocolate to the meringue mixture. Fold in the cocoa and chocolate until everything is evenly distributed.

Line a baking tray with greaseproof paper or a non-stick baking sheet (I love these bake-o-glide sheets).

Put your meringue mixture into a large piping bag fitted with a star nozzle.

Start by piping a dot in the centre of your meringue nest, then in one continuous motion go around the dot twice to make a bigger circle and then go around the outside twice to build the sides. If you don’t really like piping then you can simply make 10 dollops of meringue on your baking sheet then use the back of a tablespoon to make a dent in the centre. There’s a little video here if you’d prefer to watch how piping is done.

Bake the meringues for 1 hour 45 minutes. Once cooked turn off the oven and leave them to cool in the oven. It’s best to leave them to cool slowly in the oven but if you’re in a bit of a hurry then remove them from the oven and cool them on a rack (they’re slightly more likely to crack if cooled more quickly).

Serve.