Mix the basic overnight oat ingredients in a glass, or if storing, a storeable container such as a jar with a lid, or tupperware.
Next, add the diced apple (you can save a couple of pieces for topping), the extra cinnamon, the chopped nuts, and mix together.
Add the extra apples on top, and the crushed biscoff biscuits if using.
Set in the fridge overnight, or for at least 2-3 hours to set. Enjoy the next morning, perfect with an extra small drizzle of maple syrup on top!
