Preheat 450 degrees, line a cookie tray Silpat and set aside.
Take a liquid measuring cup, pour 1 TB of vinegar, then add the vegan milk to the 1 cup line, stir, and set aside.
Take a medium-sized bowl and combine the flour, salt, baking powder, and sugar and stir to combine.
Take a cheese grater and grate your cold vegan butter, then stick it in the freezer for 5 minutes or more. *OR you can take cold or frozen vegan butter and use a pastry cutter
Add the cold vegan butter and mix it with the pastry cutter until combined. Now add ¾ of the vegan milk and stir just until mostly combined. If your dough is too dry, add some vegan buttermilk slowly.
Then dump out on a Silpat. Flour your hands and pat the dough down, then fold it over and fold again, fold about four times and then pat into a thick round.
Take a sharp knife and cut the dough into small squares.
Take a 9x13 pan and grease it and then place the squares evenly on the bottom of the pan.