For the Crust:
1 ½ cups shortbread cookie crumbs
1 cup all-purpose flour
½ cup brown sugar
½ cup cold butter
For Cheesecake Filling:
(2) (8 oz) packages cream cheese softened
2 cups white sugar
(4) tbsp all-purpose flour
½ cup lemon juice
3 tbsp lemon zest
½ tsp baking powder
4 tsp confectioners’ sugar
Preheat oven to about 350 degrees F (175 degrees C). Line a 9×13-inch baking pan with aluminum foil.
Add and mix the shortbread crumbs, flour, and brown sugar in a medium bowl. Cut butter using (2) knives or a pastry blender until the mixture resembles coarse crumbs. Press it over the bottom of the prepared pan.
In the preheated oven, bake it for 15 minutes.
Meanwhile, beat the cream cheese and white sugar using an electric mixer until well blended. Add eggs and flour. Mix well. Blend in lemon juice, lemon zest, and baking powder. Pour filling over the crust.
Bake until the center is set for 25 to 28 minutes in the preheated oven. Let cool completely, at least 45 minutes. Refrigerate until well chilled, about 2 hours. Sprinkle with confectioners’ sugar right before serving.
Make sure not to overbeat the batter. You want to mix all the ingredients well, but if you overbeat, then the batter gets too much air, and it will cause the cheesecake bars to puff up when you bake, then collapse when you take it out of the oven.