Put 2-3 ice-cubes in a wine glass. Rub 3 mint leaves on the inside wall of a glass to develop the mint aroma, then place them on the ice cubes.
Wash ½ lime with water and cut it into small pieces. Squeeze the lime pieces lightly and put them in the glass.
Now add 4 cl elderflower liqueur, then 120 ml Luxembourgish crémant and sparkling water (to taste).