1. Heat the oven to 100°C/fan oven 90°C, Gas Mark ¼. Line a baking sheet with non-stick baking parchment.
2. Pour the egg white into a clean, grease free dry bowl. Beat the egg whites for several minutes with an electric whisk, or in a mixer, until they are thick and hold firm peaks when you raise the beaters. Keep beating, gradually adding the caster sugar a tablespoon at a time, until it is thoroughly incorporated and you have a very thick, glossy meringue. Fold the coffee into the meringue; don't worry if it's slightly streaky and uneven.
3. Pipe or spoon the meringues on to the baking tray.
4. Bake in the oven for two hours, then remove from the oven and set aside to cool completely. Carefully remove the meringues from the paper. Use at once or store in an airtight container for a few days. Airtight is important, or they will start to soften.
5. When ready to serve sandwich the meringues with the lightly whipped cream and dust with the cocoa powder.
Tip: Flavour the cream with a coffee flavured liqueur for added luxury.
Recipe courtesy of RSPCA Assured