Blueberry Crumb Bars

Ingredients
1 cup white granulated sugar
1 teaspoon baking powder
3 cups all-purpose flour
1 cup unsalted butter
1 egg
1 teaspoon pure vanilla extract
1/2 teaspoon kosher salt
zest of two lemons

4 cups fresh or frozen blueberries
1/2 cup white sugar
3 teaspoons cornstarch

Method
1.Preheat the oven to 375 degrees F (190 degrees C). Line a 9×13 inch pan with parchment paper and spray with nonstick cooking spray.
2.In a medium bowl, stir together 1 cup sugar, 3 cups flour, salt, lemon zest and baking powder.
3. In a small bowl, whisk the egg and vanilla together until combined.
4. Use pastry cutter or your food processor (see not below for alternative method) to blend the flour mixture with the butter and egg/vanilla mixture. Dough will be crumbly. Pat half of dough into the prepared pan.
5. In another bowl, stir together 1/2 sugar and cornstarch. Gently mix in the blueberries. Sprinkle the blueberry mixture evenly over the crust. Crumble remaining dough over the berry layer.
6. Bake in preheated oven for 45 minutes, or until top is slightly brown. Cool completely before cutting into squares.

Note: If you do not have a pastry cutter or a food processor, simply freeze your butter and use a box grated to grate the butter into the flour mixture. Use two forks or your fingers to fully incorporate.