Line 1 or 2 (depending on the size) baking sheets with parchment or a silicone baking mat.
Weigh out the coconut oil or vegan butter (or both) and place in the freezer to harden. In a small bowl or measuring cup (with a spout will be easier), combine the milk, lemon zest, lemon juice and vanilla and set aside to curdle.
In a large bowl (large but shallow is best), whisk together the flour, sugar, baking powder, baking soda and salt.
Add the coconut oil or vegan butter (or both) to the flour mixture. If using vegan butter, you can aslo grate it in. Use your fingrtips or a pastry cutter to incorporate the fat into the dry ingredients until you get a breadcrumb consistency. If a few pea-sized chunks remain that’s ok.If you feel the fat softening or melting, stick the bowl in the fridge or freezer for a few minutes until cold, then continue. Add the blueberries, then drizzle in the milk while mixing to minimize dry spots. Mix carefully to avoid bursting the blueberries.If using frozen blueberries, don’t let them thaw. Add them frozen, toss them in the flour and butter mixture until well coated, then add the milk and follow the same instructions. Once a shaggy dough forms (it will be crumbly, that’s normal) tip it all out onto a lightly floured cutting board (that way it’s easy to put in the fridge) and press it into a circle about 2.5cm/1 inch thick. If it softens too much, place it in the fridge. If not, cut it into 8 even triangles, brush the top with milk and sprinkle the whole surface with coarse sugar (optional).
Place the scones on the prepared baking sheets, leaving room for spreading and place them in the fridge for about 30 minutes to chill.
In the meantime preheat your oven to 180°C/350°F.
Bake them for 25-30 minutes or until they’re lightly golden on the surface and firm to the touch.
Let them cool about 5 minutes on the tray before transferring them to a wire rack and topping with the glaze!