Peach and Blackberry Crisp

I had some peaches from the market sitting on my counter, begging to be used.  I didn't want to eat five peaches at that moment and I have been craving a baked fruity dessert for quite some time now.  I recently saw this peach and blackberry cobbler, which got me thinking that I should use the blackberries in my fridge in this baked dessert.  I didn't want to make a cobbler with a biscuit topping, though - I was looking for more of a crisp/strudel type topping.  I visited a few of my favorite recipe sources online and found this plum and peach crisp recipe, which I had wanted to try last year when I first started cooking.  I decided to use that recipe as a base.  I didn't measure the fruit at all, but stuck with the 1/4 cup of sugar.  I think the tartness of the blackberries definitely needed it.  The "crisp" topping was not exactly crisp - it was more like a chewy oatmeal cookie, which was absolutely delicious!  This was a fun, impromptu dessert (and breakfast!) which can definitely be made again and with other fruit as well.  I think some apples would be delicious in the fall/winter - maybe with some cinnamon - the oatmeal cookie-like topping would go great with apple and cinnamon, and maybe I'll add some walnuts too.  There are so many ideas and flavor profiles to play with here!  (I would be happy to take some suggestions, too.)