01 -
Set your oven to 375°F, then grease a 9"x13" pan with spray. Stick a parchment paper sheet on the bottom.
02 -
Stir the butter, flour, cinnamon, sugar, brown sugar, and baking powder together. Add eggs and almond extract and mix until smooth.
03 -
Save 1½ cups of the mixture for topping. Spread the rest on the bottom of the pan, pressing it firmly.
04 -
In a bowl, whisk together lemon juice, sugar, and cornstarch. Toss in blackberries gently and pour over the crust.
05 -
Crumble the reserved dough on top of the berries. Bake 40-45 minutes until it turns golden. Let it cool totally before cutting.