Beat egg whites until stiff. Gradually add sugar until a shiny, stiff mixture is formed. Mix the almonds together with the cocoa powder and sprinkle over the mixture, folding in carefully with a spatula. Place the mixture into a piping bag. Squeeze about 60 small dollops (about 2.5 – 3 cm diameter) onto a baking sheet that has been lined with baking paper. Flatten each dollop using a small cooking knife. Bake in a preheated oven at 180°C (gas mark 2 – 3, or fan-oven: 160 °C) for about 15 minutes. Leave baking sheet in the oven after it has been turned-off and open the door for about 5 minutes. Then remove the macaroons and leave them to cool.