Preheat your oven to 400°F and line a baking sheet with parchment paper.
In a small bowl, whisk together the non-dairy milk, vanilla, and apple cider vinegar. Let sit for 5 minutes to curdle, creating a vegan buttermilk.
In a large bowl, add the sugar and lemon zest. Using your fingers, rub the two together for 2-3 minutes until the sugar is fragrant and the zest is fully incorporated.
To the bowl with the lemon sugar, add the flour, baking powder, and salt. Whisk everything together until well combined.
Grate the cold, vegan butter directly into the flour mixture. Use a pastry cutter, fork, or your fingers to work the butter into the flour until it resembles coarse crumbs, with pea-sized pieces throughout.
Pour the wet ingredients into the dry mixture and gently fold with a spatula until the dough just comes together. Be careful not to overmix – a slightly shaggy dough is ideal.
Turn the dough out onto a lightly floured surface and pat the dough into a 1-inch thick round and cut into 8 triangles. Transfer to the prepared baking sheet, spacing them out to allow for even baking. Bake for 20-25 minutes or until the scones are golden brown.
While the scones cool, whisk together the powdered sugar, lemon juice, and vanilla until smooth. Adjust the consistency as needed with more powdered sugar or lemon juice.
Once the scones have cooled, drizzle with the lemon glaze and sprinkle with fresh lemon zest!