Peel, core and slice apples into thin wedges. Spread apples and blueberries in baking dish.
Stir oats, brown sugar, flour and cinnamon together in mixing bowl. Add softened butter in chunks and rub into oat mixture with fingertips (or cut in with pastry cutter) until the butter is well incorporated and the mixture is crumbly.
Crumble evenly over the blueberry-apple mixture and loosely cover with foil.
Bake, covered, for 20 minutes. Remove foil and bake open for an additional 25-30 minutes, until the topping is golden brown and the juices from the filling is bubbling. Serve immediately (see notes for serving suggestions).
Notes
Serving suggestions:
The blueberries in this recipe can be switched with your favorite seasonal fruit. I recommend trying it with peaches, mixed berries, cranberries, plums, or apricots for a variation on this delicious dessert.
I highly recommend adding a scoop or two of vanilla ice cream for extra decadence.
This recipe can be divided and baked in individual ramekins for a personal, fancy touch.