Fruit: Stir together sugar and cornstarch. Gently mix in the blueberries.

Dough: Preheat oven to 375°F, coat a 9×13 pan with cooking spray.

In a medium bowl, stir together 1cup sugar, 3 cups flour, and baking powder.

Mix in salt and vanilla.

Use a fork to blend in butter and egg. Dough will be crumbly.

Pat half of dough into pan.

Layer blueberry mixture evenly over the crust and crumble remaining dough over berry mixture.

Bake 45 minutes or until brown on top.

Cool completely before cutting.