Melt the butter and let it cool down a little. Coarsely chop the waffles, put them in a freezer bag and crumble them with a cake roll. Mix butter and waffle crumbs, place on the bottom of a springform pan (24 cm Ø) and press flat. Put the pan in a cold place. Soak gelatine in cold water. Halve the lemon and squeeze the juice. Mix cream cheese, sugar, liqueur and lemon juice with the whisk of the hand mixer until smooth.
Add yoghurt. Dissolve squeezed gelatine in a small pot. Stir in 3 tablespoons of cream, then stir into the remaining cream. Spread the cream wavy on the crumb base and refrigerate for at least 4 hours. Cut out balls of different sizes from the melons. Cut the cake into 12 pieces and decorate with melon balls and pistachios
4 hours waiting time