Makes 9:
Preheat the oven to 190°C / gas mark 6.
In a large bowl, mix with hands to the consistency of rough breadcrumbs:
Place half of the crumble mixture in the bottom of a lined glass dish. Use wet hands to press it down, then bake for 15 minutes.
Meanwhile, slice 500g blueberries into halves.
Spread the blueberries over the cooked bottom crust and top with the remaining crumble mixture.
Bake for 25 minutes, until the berries are bubbling and the topping is golden brown.
Let cool before slicing into bars.
Modified from The Pretty Bee