Wash the grapes, cut in half, remove the seeds and pour the grapes into glasses or serve on plates. Scatter the almond slivers over the top. Dissolve the sugar in the juice of the ½ lemon and drizzle the juice over the grapes. Mix the cream, vanilla sugar and yoghurt and pour a little over the grapes.
Garnish with whipped cream, grapes, sliced almonds or lemon balm, if you like.