Fresh blueberries are a yummy addition to lemon bars. For a different look, cut the bar cookies on the diagonal to make diamonds instead of squares.
Heat oven to 350 degrees F. Line 13 x 9 x 2-inch baking pan with aluminum foil. Coat with nonstick cooking spray.
In bowl, stir together butter, powdered sugar, vanilla and salt. Gradually stir in flour until smooth. Press dough over bottom of prepared pan.
Bake in 350 degree F oven 20 minutes or until edges brown.
In large bowl, mix granulated sugar and flour. Whisk in eggs until smooth. Stir in lemon rind and juice. Fold in berries. Pour filling over crust.
Bake in 350 degree F oven until set, 30 minutes. Let cool in pan on wire rack. Dust with the 1/4 cup powdered sugar. Cut into diamonds. Makes 20 diamonds.