Preheat the oven to 375ºF and coat a 9x9 baking dish with baking spray.
In a food processor, combine flour, sugar, baking powder, and salt. Then add butter and pulse until small crumbles appear. Add the egg and pulse until combined.
Press 3/4 of the dough into the prepared baking dish.
In a bowl, whisk together sugar, cornstarch, and lemon juice. Gently fold in the raspberries and coat evenly. Spread the raspberry mixture evenly over the crust.
Crumble the remaining dough evenly over the raspberry layer
Bake for 45-50 minutes or until the top is light golden brown. Cool the bars completely before cutting into squares.
Cover and store leftovers in the refrigerator.