Black and Blue Oat Bars

Really delicious! A bit more time consuming than some other bar recipes I've made, since the crust and crumble topping are not the same mixture (as in DeMasco's Back to School Raspberry Granola Bars for instance). The bottom is a shortbread crust while the topping is traditional crumble. I halved the recipe (using weights) and my own blueberry mixture which I had made for another use (but very similar). I will say my bottom crust was much thicker than the photo (like 3 x thicker) but it did get cooked through and was a perfectly tender, slightly sweet enough base.