Preheat the oven to 375 degrees. Grease a 9×13 inch pan (I like to also line mine with foil). In a food processor, combine sugar, flour, baking powder and salt. Plus to combine. Add egg, pulse to combine. Add in cold butter pieces and pulse until mixture is crumbly and holds together. *You can also do this in a bowl by combining ingredients and using a pastry cutter. Press half of the mixture into your baking pan and set aside. In a bowl combine berries, sugar, cornstarch and lemon juice and zest. Gently stir to evenly coat berries. Spoon berries over prepared crust. Sprinkle remaining crust over berries. Bake in preheated oven for 45-55 minutes, or until top is slightly brown. Cool prior to cutting. These store best in the refrigerator, but can be heated up and topped with ice cream for serving if desired.