01 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
02 - In a medium bowl, whisk together the flour, baking powder, baking soda, and salt until well combined.
03 - In a large bowl, whisk together melted coconut oil and sugar. Add applesauce, lemon juice, lemon zest, and vanilla extract. Whisk until smooth and creamy.
04 - Gradually mix the dry ingredients into the wet mixture until just combined. Do not overmix.
05 - Gently fold in the blackberries, being careful not to crush them excessively. The dough will be soft and slightly sticky.
06 - Using a cookie scoop or tablespoon, drop rounded spoonfuls of dough onto the prepared baking sheets, spacing about 2 inches apart.
07 - Sprinkle each cookie with coarse sugar if desired for extra texture and sweetness.
08 - Bake for 11-13 minutes, or until the edges are set and lightly golden.
09 - Allow cookies to cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely before serving.