Place the cocoa and coffee in a saucepan with 80 ml water and stir over low heat until dissolved. Let cool.
Butter well 6 ramekins and sprinkle the inside with extra caster sugar shaking off any excess.
Whisk the egg whites in an electric mixer until soft peaks form. Slowly add the caster sugar and cream of tartar and continue to beat until stiff peaks form.
Gently fold a little egg white into the mocha mixture then add mixture to remaining egg whites .Fold in to just combine keeping as much air in the mixture as possible.
Fill each ramekin to the top. Place on a baking tray and bake for 12-15 minutes until well risen.
