Mix together the oats, yogurt, grated apple, granulated sweetener, cinnamon and vanilla
Place this mixture in the bottom of a Kilner jar (the jar should be able to hold up to 350ml)
In a clean bowl, mix together the "custard" ingredients - fat free natural yoghurt, quark, vanilla extract, chia seeds and granulated sweetener. Beat it well to remove any lumps
Pour this mixture on top of the oat mixture, close the lid and refridgerate overnight