Crust:
4 cups all-purpose flour
1 cup powdered sugar
1/4 teaspoon salt
1 lb. plus 4 tablespoons chilled butter , cubed
Filling:
3 cups granulated sugar
1/4 cup flour
1/2 teaspoon baking powder
7 eggs, lightly beaten
grated zest and juice from 4 lemons
6 oz. blueberries
powdered sugar for dusting finished cookies
Preheat oven to 350 degrees. Lightly grease a 17×12 inch x 1 inch jelly roll pan; set aside.
In the bowl of a food processor fitted with a metal blade, combine the dry ingredients for the crust and pulse 2-3 times until combined. Add the chilled butter cubes and process until the mixture comes together into a dough ball. Press the dough evenly into the pan and 1/4 inch up the edges of the prepared pan. Bake for about 12 minutes or until beginning to turn golden brown and just slightly under done. Remove from oven and allow to cool.
Meanwhile prepare the filling in a separate bowl. In a bowl whisk the eggs and sugar together until combined. Add the juice and zest and combine. Sift in the remaining filling ingredients except the berries and stir to combine. Pour the filling over the cooled crust . Sprinkle evenly over the filling the blueberries. Bake at 350 degrees for about 25 minutes or until set. Remove from the oven and allow to completely cool. Carefully cut into squares and dust them with powdered sugar.
For thicker bars these can also be made in a 9x13x2 inch pan . Complete as the recipe states except pat the dough half way up the sides and bake a little longer. The crust may puff up during baking; if this happens, remove from oven and gently press back down and continue to bake crust as directed. Once crust is filled with lemon/blueberry mixture bake as directed but as long as needed to become firm. Cool several hours before cutting.