Preheat oven to 180 degrees C. Take a 23cm cake tin and trace around the bottom on baking paper with a pencil. Put the baking paper on a baking tray.
Whisk the egg whites with an electric mixer until the soft peak stage. Now, while still whisking, add the sugar, one tablespoon at a time, until stiff peaks form.
Combine the grated chocolate, almond meal and cornflour. Sprinkle 1/3 of the mix over the egg whites and fold through. Add the remainder just to incorporate, don't mix too much. Using a spatula, spread the mixture over the circle you marked on the baking paper. Sprinkle the flaked almonds over the top.
Put the baking tray in the oven and immediately turn the heat down to 140 degrees C. Cook 1 hour then turn off the heat and let the meringue cool completely in the oven.