Secure the baking parchment to the baking sheet using a small dab of the meringue in each corner. Spoon the rest of the meringue into the middle of the circle template, then use a palette knife or silicone spatula to shape it into a thick disk, creating some swirls, dips and peaks as you do. Dust the meringue with the cocoa powder using a fine sieve, then transfer to the middle shelf of the oven. Reduce the temperature to 140/120C fan/gas 1 and bake for 1 hr 20 mins. When the time is up, turn off the oven, leaving the meringue inside to cool fully (ideally, leave overnight). Once cool, the meringue will keep in a cool, dry place for up to two days. Don’t chill, as the moisture will cause it to become sticky.
