Add the 2 tbs of apple cider vinegar to the ¾ cup soy milk and mix. Set aside to curdle.
In a large bowl, mix the 2 cups gluten free flour blend, 4 tbs potato starch, 1 tbs baking powder, ½ tsp baking soda, 1 tsp salt, and 6 tbs vegan butter together. Using your fingers (or a paddle of a standing mixer) mix until the butter is broken down and the dough forms tiny pea sized pieces.
Mix in the curdled soy milk until it comes together into a stiff dough.
Turn out the dough on a floured surface and shape into a ½"-¾" tall square.
Cut the dough into 9 equal squares.
Arrange on a lined baking tray. Bake for 25 minutes.
Let the biscuits cool before eating.
Serve with vegan butter or jam!