I love how buttery the topping is. I added 4 Tablespoons of flour to this crumble and it still was runny after baking, not in a bad way just not in the thick like a can of pie filling thick way that I was hoping for. Not that canned pie filling should be something to aspire to, but I do like a bit of thickness to the fruit juice in my crumble. I used to use instant Tapioca to thicken it, but lately have been using flour, which strikes me as old fashioned (more authentic) and less processed, but maybe in the end doesn't do as good a job? Not sure, next time I'll try 6 Tablespoons.
Here it is all topped and ready for the oven (375 F for about 40 minutes)sweet rich topping.