Grease or line a loaf tin
In a bowl mix all the ingredients together, apart from the chocolate. The mixture should hold together. If too dry slowly add more tahini. If too wet, add more oat flour slowly.
Reserve about a ¼ cup of the mixture (for the topping)
Pour the remaining mixture into a loaf tin and use your fingers to really press it together.
Pour over the melted chocolate, spread evenly.
Crumble on the remaining oat mixture
Refrigerate until set
