Prep + Wet Ingredients: Preheat the oven to 350 degrees F (176 C). Line a baking sheet with a silicone liner or parchment paper, or grease generously. In a small bowl or liquid measuring cup, whisk together the coconut milk, vanilla extract and egg. Set aside.
Dry Ingredients: In a large mixing bowl, whisk together the gluten-free flour, sugar, salt, and baking powder.
Add the Butter: Chop the butter into medium-sized pieces and work it into the dough with a pastry cutter or your hands. When finished, the pieces of butter should be blueberry sized or smaller and it should be well distributed into the dough.
Add the Blueberries: Add the blueberries to the dough and mix in gently with a silicone spatula or wooden spoon.
Combine Wet and Dry ingredients: Add the wet ingredients to the dry ingredients and gently mix with the spatula or spoon until just mixed but uniform in texture throughout. It may seem a bit dry and crumbly but that's ok for this recipe!
Form a Disc: Flour both sides of your hands generously and form a large ball of dough in the center of your baking sheet. Use your hands to compact the dough in a ball before pressing it into a disk about 7-8 inches in diameter. It may still be quite crumbly but as long as it is roughly sticking together, that's just perfect! Be careful not to squish the berries.
Prep for Baking: Cut the disk into 8 equal sections with a sharp knife. Then use a brush or your fingers to lightly coat the pieces with milk.
Bake: Bake for 22 minutes. Then remove the scones from the oven and use a greased knife or thin spatula to separate the wedges from each other just a little bit, so they can bake and get crisp. Return to the oven for another 6-8 minutes or until the scones are set and lightly golden brown on the outside.
Glaze: Meanwhile, add 1 tablespoon of lemon juice to to the powdered sugar and whisk until smooth. Add more juice in small increments as desired to thin.
Cool: Cool on a cooling rack before glazing and topping with fresh grated lemon zest for decoration. Or if you can't wait, allow them 10 minutes to cool and drizzle on some glaze and zest right before eating!