Bake a pancake. Beat the cream for the mousse until soft peaks form. Heat the coulis and sugar together, then add the gelatine which you have allowed to soak for a little while first. Let the coulis cool down to 30°C and then fold it quickly but gently into the cream. Put in the refrigerator to firm up. Roll up the cold (room temperature) pancake into a tube and use a pastry bag to pipe the stiffened mousse all the way through it. Finish off by sprinkling the pancake with icing sugar.