I am a sucker for fresh blueberries! I grew up stuffing myself with them in South Jersey (Yes, Virginia, NJ is actually a nice place!) and the love affair continued into my adulthood. Each year I buy at least one flat of them if the wild pickings are not great. This is but one of my favorite blueberry recipes.
Preheat oven to 375 degrees. Butter an 9x13 baking dish, set aside
In a large mixing bowl whisk together flour, 1 cup granulated sugar, baking powder, salt and lemon zest. Add beaten egg and cold butter cubes to flour mixture and using a fork or a pastry cutter (or even your fingertips, or two table knives), cut mixture together until it resembles coarse crumbs. Gently press 2/3 of the mixture evenly into prepared 9x13 dish.
In a separate mixing bowl, whisk together remaining 1/2 cup granulated sugar and 4 tsp cornstarch. Stir in lemon juice then add blueberries. Toss mixture to evenly coat then pour and spread coated blueberries evenly over crust in baking dish. Sprinkle remaining crumb mixture over berry layer (I pressed some of the mixture together in my hands while sprinkling to make larger crumbs). Sprinkle (optional) Turbinado sugar evenly over top.
Bake in preheated oven for about 38 - 42 minutes until top is golden brown. Allow to cool for about 20 - 30 minutes before cutting into squares (or serve warm with vanilla ice cream, yum). Store bars in an airtight container in refrigerator. (You may want to bring them up to room temp before serving, though.) I wrapped each in a little slice of waxed paper to keep them from mooshing together.