Preheat the oven to 375 degrees. Spray a 9x13-inch pan with non-stick cooking spray.
In a medium bowl, stir together flour, 1/2 cup sugar, brown sugar, baking powder, salt and cinnamon. Use a pastry cutter or fork to mix in the butter and egg until well combined and crumbly. Pat half of the dough into the prepared pan. Bake for 10 minutes.
In another bowl, stir together 1/2 cup sugar and cornstarch. Gently fold in the blueberries. Sprinkle the blueberry mixture evenly over the crust. Crumble remaining dough over the berry layer. ( I like to squeeze the dough in my hand to make bigger crumble.)
Bake for 30-35 minutes, or until top is golden brown. Cool completely before cutting into squares.