In a small bowl toss together the blueberries with the cornstarch and the sugar until well-coated. Put blueberries into two ramekins (I used Aplico #3 which are about 10 ounces each) and set aside on a rimmed, foil-lined baking sheet.

In another small bowl combine the flour, oats, brown sugar, and salt. Cut in the butter with a pastry blender and use your hands to work it all together, working the butter into the dry ingredients until the mixture is crumbly.

Sprinkle the crumble mixture over the berries and bake for 30 minutes, or until the berries are bubbly and the topping is golden.