01 -
Set your oven to 375°F. Grease a 9"x13" pan with spray, then line the bottom with parchment paper.
02 -
Stir together the melted butter, flour, cinnamon, baking powder, both sugars, eggs, and almond extract until it's all combined.
03 -
Set aside 1½ cups of the crust mix. Press the rest into the prepared pan to form the base.
04 -
In a small bowl, mix cornstarch, sugar, and lemon juice. Carefully coat the blackberries in the mix, then spread it across the base.
05 -
Sprinkle the reserved crust mix evenly over the filling. Bake for 40-45 minutes, or until it's nicely golden. Let it cool completely before cutting it into pieces.