First, preheat the oven to 400F and line a baking tray with parchment paper.
Next, add the soy milk and apple cider vinegar to a bowl, stir, and let sit until the milk begins to curdle. This is the process to make a vegan buttermilk.
While the milk is curdling, add the flour, baking powder, and salt to a separate bowl and sift together. Then add in the cubed vegan butter and use a pastry cutter or fork to 'cut" the cutter into the dough until you have a crumbly dough.
Next, pour the vegan buttermilk into the bowl of dry ingredients and butter. Then, gently mix everything together until you have a shaggy dough. Remember, you do not want a smooth dough- the dough should be lumpy but not have any dry spots of flour.
Turn the dough out onto a surface. Then, fold in half over itself and use your hands to gently flatten layers together. Rotate the dough 90 degrees and fold in half again, repeating this step 2-3 times but taking care to not overwork the dough.
Use your hands (do not use a rolling pin) to flatten the dough to 1" thick and lightly dust a 2 ¾" round biscuit cutter with flour. Press the biscuit cutter straight into the dough and drop the biscuit onto your prepared baking sheet.
Add the biscuits to the parchment lined baking tray so they are about ½ inch apart from each other and bake for 18-20 minutes or until fluffy and brown. If desired, brush the tops with a little extra melted butter before and after baking. Serve immediately with extra butter & jam and enjoy!