Peel the ginger and cut into 16 thin slices. Wash the lemon, grate it dry and peel off broad, long pieces from the peel. Wrap 4 zests around the stem of a wooden spoon. Wash the cucumber, grate dry and peel the peel in thin strips
Divide the ginger slices, remaining lemon zests and half of the cognac between 4 glasses. Crush the ginger and lemon zests a little with a wooden pestle. Add ice cubes and stir. Spread the rest of the cognac, lemonade and cucumber peel evenly over the glasses. Stir again. Remove the lemon zests from the wooden spoon handle and decorate the glasses with them