Beat the margarine for roughly 2-3 minutes until frothy. Alternately add the powdered sugar and eggs, stirring well after each addition. Mix the baking powder with the flour, then stir into the mixture. Fold in the grated chocolate and ground almonds.
Spread the batter onto a baking sheet lined with baking paper.
Bake at 180°C (350°F) for about 20 minutes until golden.
Once the cake is cooled completely, spread the melted couverture over it. Decorate with chocolate flakes, colorful sprinkles, almonds, and grated coconut. Let cool until the couverture sets, then cut into small squares.