Stir the natural yoghurt with the vanilla sugar until smooth. Drain the juice from the apricots. Puree the apricots with a hand blender except for a few for decoration.
Pour a layer of apricot puree into the prepared glasses, then pour in a layer of the yogurt. Place a large chocolate crossie in the middle of the yogurt layer and cover it with the next layer of apricot puree. Keep layering until everything is used up.
Finally, place a chocolate crossie and a piece of apricot on top as a decoration. Chill until consumption.