Preheat the oven to 400F. Butter or grease an 8×8-inch baking dish and set aside.
In a large bowl, add blackberries, ½ cup sugar, cornstarch, lemon juice, salt, and ground cinnamon.
Carefully stir until the blackberries are completely covered.
Add the blackberries to the prepared baking dish and set aside.
Mix together the almond milk and apple cider vinegar and let sit for 5 minutes. Set aside until ready to use.
In a large bowl, mix together the gluten free flour, granulated sugar, baking powder, and baking soda.
Then, with a pastry cutter, work in the vegan butter until the texture is like sand with some larger butter pieces the size of a pea.
Add in the almond milk mixture and stir until the dough is smooth.
Place big dollops of the dough on top of the blackberry filling. Sprinkle the top with turbinado sugar.
Bake at 400F for 35-40 minutes, until the top is golden brown and the fruit is bubbling.
Serve with coconut whipped cream or vegan vanilla ice cream.