Let strawberries thaw at room temperature. Then puree. Measure 150 g puree for the sauce and cover and chill.
Beat the eggs, vanilla sugar and sugar with the whisk of the mixer until thick and creamy. Stir in the yoghurt and remaining strawberry puree. Whip cream until stiff and fold in 2 portions. Pour the mixture into a bowl or mould. Cover with foil and place in the freezer overnight.
Remove ice from the freezer. Stir cold strawberry puree until smooth. Form ice cream into balls and serve with strawberry sauce. Serve with lactose-free whipped cream.