01 - Preheat the oven to 350°F and line two baking sheets with parchment paper.
02 - In a medium bowl, whisk together the flour, baking powder, baking soda, and salt until well blended.
03 - In a large bowl, beat together the sugar, melted coconut oil, plant-based milk, and vanilla extract until smooth and creamy.
04 - Gradually stir the dry ingredients into the wet mixture until just combined. Take care not to overmix.
05 - Gently fold in the quartered blackberries, being careful not to crush the fruit.
06 - Scoop tablespoon-sized portions of dough, roll into balls, and coat each ball in the additional sugar.
07 - Place the dough balls 2 inches apart on the prepared baking sheets and flatten slightly with your palm.
08 - Bake for 11 to 13 minutes, until the edges are set and lightly golden.
09 - Let the cookies rest on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.