Ingredients

• 3/4 cup all-purpose flour
• 1/4 cup cornstarch
• 1/4 cup powdered sugar
• 1/4 cup white sugar
• 6 tablespoons butter
• Filling:
• 3/4 cup white sugar
• 3 eggs
• 2 tablespoons cornstarch
• 1/2 teaspoon baking powder
• 7 tablespoons lemon juice
• 1 1/2 tablespoons lemon zest

Directions

Preheat oven to 350 degrees F (175 degrees C). Line a 7 x 11-inch baking pan with foil; spray with cooking spray. Combine flour, 1/4 cup cornstarch, 1/4 cup powdered sugar, and white sugar in a bowl. Mix in the butter; and stir until well mixed and crumbly. Press mixture in bottom of prepared pan. Bake in preheated oven until lightly golden, about 15 minutes. Mix 3/4 cup white sugar, eggs, 2 tablespoons cornstarch, baking powder, lemon juice and lemon zest together in a mixing bowl using an electric mixer or wire whisk. Blend thoroughly. Pour filling over hot crust. Return pan to oven and continue baking until filling is set, 18 to 20 minutes. Cool completely before cutting into bars. Sprinkle with powdered sugar if desired.