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Preheat oven to 375F.
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Lightly grease a 9x13-inch baking pan.
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In a mixing bowl, combine 1/2 cup sugar, brown sugar, baking powder, and flour.
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Slowly mix in butter, egg, and vanilla until the mixture is well combined and resembles coarse crumbs.
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Press half of the crumb mixture into the bottom of the pan.
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In a separate bowl toss together 1/2 cup sugar, blueberries, and cornstarch.
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Evenly sprinkle the blueberry mixture evenly over the crust.
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Evenly sprinkle the remaining crumbs over the top of the blueberry mixture.
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Bake for 40 minutes or until the top is lightly browned.
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Allow to completely cool before cutting.