Soak gelatine in cold water. Stir together the jelly, sugar and lemonade and heat until the sugar and powder are dissolved (do not boil!). Squeeze the gelatine and dissolve it in the warm jelly, then chill. Melt butter. Put rusks in a freezer bag and crumble coarsely. Mix butter and rusk. Grease the bottom of a springform pan (22 cm Ø).
Press crumb mixture flat on it and put it in a cool place. As soon as the jelly is cold (approx. 1 hour), whip cream until stiff and fold into the jelly. Halve the chocolate bars and spread them on the edge of the springform pan with the round side facing outwards. Pour in the cream and chill for about 2 hours. Wash lemon and orange, grate dry and halve. Cut one half into slices, from the other half cut spirals from the shell with a julienne nipper. Decorate Charlotte with the slices and spirals