Preheat oven to 450°F and line a baking sheet with parchment paper.
In a large mixing bowl, whisk together the flour, salt, baking powder, and ⅓ cup of granulated sugar.
Add in the cold butter, then use a pastry cutter or fork to cut the butter into the dry mixture (photos are in the post above for reference). The mixture should resemble the texture of sand.
Pour in the buttermilk and use a wooden spoon to mix until combined. Do not over-mix. The dough will be fluffy.
Transfer the dough to a floured surface, then cover your hands with flour and form the dough into a rectangle, around 1 inch thick.
Fold one short side of the rectangle of dough towards the middle, then fold the other side in (so you have a square). Gently flatten the log again, then repeat twice more (folding it into a square 3 times total). Work quickly so that you handle the dough as little as possible.
After the final fold, form the dough into a ¾ inch thick rectangle. Use a biscuit cutter to cut circles in the dough. Do not twist the biscuit cutter when removing it - either pull the dough away from the sides or lift straight up (SEE NOTES).
Place the shortcakes onto the baking sheet, making sure they are touching each other. Lightly brush the top of each biscuit with more vegan milk, then sprinkle with coarse sugar. Bake until lightly golden brown, around 13-17 minutes. If making the whipped cream from scratch, make it while they bake. You can also use your favorite store-bought vegan whipped cream (I like So Delicious Cocowhip)