Cut the peaches into wedges. Skin and core fresh peaches beforehand. Cut the lemon into thin slices. Halve the kumquats lengthways.
Put the fruits in a bowl. Pour in the peach liqueur and peach juice and pour the sugar over it. Mix everything together briefly, then cover and let cool for at least 2 hours.
Then pour into a large jug - alternatively a punch bowl - and pour on the cava or sparkling wine. Stir everything and add the ice cubes. Garnish the filled glasses with a few mint or lemon balm leaves.