Wash and drain the grapes well, pluck them from the panicles and cut them in half. Wash the apple, remove seeds and cut into fine slices. Mix yoghurt, salad cream and lemon juice together. Season to taste with salt and pepper. Wash lemon balm, dab dry and chop finely, except for a little bit for garnishing.
Stir into the sauce. Arrange the ham on a plate. Arrange grapes and apple slices on top. Spread the sauce over it. Garnish with lemon balm leaves and lemon slices