Step 1

Preheat oven to 375°F. Line a 9x13 pan with foil or parchment, and butter or spray with non-stick spray.

Step 2

Using a hand mixer or stand mixer fitted with the paddle attachment, combine granulated sugar, baking powder, flour, and salt. Add lemon zest, butter, egg, and vanilla. Beat on low speed until the butter is evenly distributed in small pieces and the mixture is crumbly.

Step 3

Dump a little more than half of the mixture into the bottom of the prepared pan. Use your hand or the bottom of a measuring cup to evenly press the dough into the pan.

Step 4

Gently stir together all ingredients until well incorporated.

Step 5

Spread the filling over the crust, then crumble the remaining dough over the top of the berries.

Step 6

Bake for approximately 40 minutes, until the top is light golden brown. Transfer pan to rack to cool, before cutting into squares. I have also refrigerated these, after cooling to room temp.