Boil up sugar and 50 ml water while stirring. Beat the egg white with 1 pinch of salt until stiff. Whip hot sugar syrup under the beaten egg white. Continue beating for a few minutes until the beaten egg white has stabilized. Stir in gelatine. Pour the mixture into a piping bag (possibly with a large perforated spout) and squirt lightly onto the biscuits. Chill for about 30 minutes.
Coarsely chop the couverture and melt it together with the coconut oil in a hot water bath, let it cool down a little. Carefully spread the liquid couverture over the meringue using a tablespoon and chill until the icing is firm. Store in the refrigerator.