Wash 400 g of grapes, cut in half and remove the seeds if necessary. Wash 400 g strawberries, remove the flower base and cut in half. 3 Wash pears, cut in half and remove the core. Wash 3 nectarines, cut in half and remove the stone. Cut the pears and nectarines into pieces. Drain the pineapple jar, catching the juice. Put the fruit in a bowl. Mix the juice of 1 lemon with 4 tablespoons of the collected pineapple juice, pour over the fruit salad and mix.
For the sauce, mix the yoghurt with 1/8 l milk and serve with the fruit salad.