Cut the vegan butter in cubes or slices. Keep them in the refrigerator along with the vegan yogurt until you’re ready to use them.
Combine the flour, cane sugar, baking powder, and lemon zest in a large mixing bowl. Cut the cold butter cubes into the dry ingredients until it’s crumbly.
Add the vegan yogurt to the bowl and gently fold it in just until everything is moistened. With floured hands, fold the dough together some more to make sure the ingredients are combined. Then, gently fold the blackberries into the dough.
Move the scone dough to a flat, floured surface such as a cutting board. Without overworking it, form the dough into a circular disc that's 1-inch in height.
Preheat the oven to 400°F. Place the scone disc in the freezer for 10 minutes and line a medium-sized baking sheet with parchment paper.
Remove the dough from the freezer. Slice it into 8 wedges and place them 1-inch apart on the lined baking sheet. Brush the tops of the scones with the plant-based milk.
Bake the scones on the top rack for 20-25 minutes. Start checking on them after about 15 minutes or so to prevent them from burning.
Remove the scones from the oven when they are golden brown and place them on a cooling rack. Make the icing by whisking together the lemon juice and powdered sugar. Drizzle it over the scones once they have cooled down and enjoy!