Preheat oven to 180 celsius. Grease 3 tart tins. Set aside.
In a mixing bowl, combine almond meal, flour, sugar, cornstarch, salt and baking powder. Add milk, oil, almond essence and mix until well combined.
Dollop almond mixture into tart tins, carefully spread it out. Smooth out the surface and top with some blackberry and sprinkle flaked almonds.
Bake at 180 celsius for 18-20 minutes, until the tart is golden and an inserted toothpick comes out clean. Remove from the oven and allow to cool down before removing from the tins.