Wash the cherries, drain and stone them. Wash the apple, grate dry, quarter it, cut out the core and cut quarters into cubes. Wash lemon hot, grate dry and cut in half.
Squeeze the juice of one half, halve the other half of the lemon and cut into slices. Wash the lemon balm, shake dry and remove the leaves.
Dissolve the sugar in the lemon juice in a bowl. Add water and cider. Add cherries, lemon slices and lemon balm, except for a few leaves for garnishing, and cover and chill for about 30 minutes.
Pour in Prosecco and serve ice-cold.