Start by making the shortbread layer. First, preheat the oven to 180 degrees C/400 degrees F. Then, in a large mixing bowl, combine the oat flour and maple syrup. It will look quite dry at first, but be patient with it and keep mixing.
When a sticky 'dough' forms, transfer it to a rectangular baking dish lined with baking paper. Bake in the preheated oven for 10 minutes. Meanwhile, start preparing the caramel.
To make the caramel, add the medjool dates, sea salt, coconut sugar, plant based milk and peanut butter. Stir over a medium heat until the sugar melts and the ingredients start to combine into a sticky mixture (around 5 minutes). Then, use an immersion blender to blend into a smooth caramel. Alternatively, transfer to a blender or a food processor and pulse/blend on a low speed.
Layer the caramel on top of the shortbread, and chill in the fridge for around 10 minutes. Use this time to melt the chocolate by putting it in a heatproof bowl over a saucepan of gently simmering water, making sure that the bottom of the bowl doesn't touch the water. Stir using a wooden spoon or a spatula until the chocolate is fully melted.
Pour the chocolate over the caramel and leave to set in the fridge for at least 30 minutes.