Preheat oven to 350˚F. Line a 9"x13" sheet pan with parchment paper.

Process oats into flour in a food processor. Add the rest of oatcake ingredients and process until combined into a stiff sticky dough. Press dough into 1 even layer into parchment lined pan. 

Slice apples into thin rounds, removing seeds from center. Toss apples slices with sugar and cinnamon. Layer apple in an overlapping pattern over dough. 

Bake at 350˚F for about 40 minutes until apple are softened and oatcake layer is cooked though. A toothpick inserted into center should come out clean. Allow to cool to room temperature and cut into bars. 

To make caramel sauce stir together all of the ingredients to combine. Pipe caramel onto bars using a pastry bag or a plastic bag with a sniped off corner.