Rinse a square spring or casserole dish (approx. 20 x 20 cm) cold and line it with cling film.
Mix vodka, 4 sachets of gelatine, citric acid and sugar in a saucepan, allow to swell according to package instructions.
Heat the vodka mixture (do not boil), dissolving the gelatine while stirring as little as possible. Pour into the mould and chill for about 1 hour.
Mix the rest of the gelatine, mint syrup, lemon juice and 100 ml of water and allow to swell and dissolve as well. Pour onto the first, firm layer.
Chill for about 4 hours. Remove firm mixture from the mould and cut out with small cookie cutters or cut into rhombuses, cubes or similar. Shelf life approx. 2 weeks when stored in a cool place.