First, add to the food processor the quick oats, nuts and a bit of salt. Chop until a fine crumbly texture and then add enough water to make a thick paste. Press the dough into a pan - it may be easiest to roll it between parchment first. Trim the dough around the edges to provide a uniform appearance. Bake the crust for about 15 minutes at 400˚F. Remove from the oven and place sliced apples on the dough-lined pan. Sprinkle over top a mix of oats, brown sugar and cinnamon.
Bake for about 30-45 minutes. The dough is quite different from regular flour dough, so keep an eye on it.
If I had to do it again, I'd use more apples. All the same, it's a nice sweet dessert.