Add the yoghurt, oats, ground flaxseed and maple syrup to your jar, then cover with a splash of milk. Mix and add a dash more milk if needed, depending on the consistency of the yogurt used.

Add a squeeze of lemon juice or a dash of water to the raspberries and mash them using a fork. Then add the mashed raspberry layer to top of the oats.

Melt the chocolate gently either in the microwave or on the hob, then pour over the raspberry layer to create a chocolate shell. Add a couple of raspberries to the top and the pistachios. Place in the fridge to set overnight or for at least 1 hour, to allow the oats to soak up the liquid.