Pre-heat the oven to 375 degrees. Grease a 9×13 inch baking dish. In a medium bowl stir together 1 cup sugar, 3 cups flour, baking powder, salt, and cinnamon.
Using a fork blend in the butter and egg until the dough is crumbly. Pat half the dough into the bottom of the prepared baking dish.
In a separate bowl stir together sugar and cornstarch. Gently mix in the fresh blueberries. Sprinkle the blueberries evenly over the crust in the baking dish. Crumble the remaining dough over the blueberry layer.
Place into the oven and bake at 375 degrees for 45 minutes or until the top is slightly brown. Remove from the oven and cool completely before cutting into squares.