Preheat the oven to 375 degrees F and spray an 8x8 baking dish with Baker’s Joy, grease with cooking spray and flour the pan, or line with parchment paper

Combine flour, sugar, brown sugar, baking powder, salt, butter, and egg in a food processor and pulse until it makes a crumbly dough

Pour about ⅔ of the dough into the prepared baking pan and press it down with the bottom of a glass to even it out

Use a rubber spatula to mix the blackberries, lemon juice, and remaining sugar in a large bowl

Spread the blackberry mixture on top of the pressed crust

Sprinkle the remaining flour mixture over the top of the blackberries

Bake bars for about 35-40 minutes, until golden brown and bubbly

Let the bars cool for about 10 minutes then remove and cut into 9 even pieces and place on a wire rack