Preheat oven to 375 degrees F.
In a large bowl, add all of the dry ingredients and whisk together.
Add the wet ingredients (not the berries yet). Stir well to combine. Add more non-dairy milk to get the batter to be thick but very moist. Shouldn't be as thin as pancake batter or as thick as cookie dough...somewhere in between.
Fold in the blackberries.
Scoop batter into nonstick muffin cups or tin.
Bake for 20 minutes and check for doneness.
Makes 9 large or 12 small muffins.