Preheat the oven to 425 degrees Fahrenheit. Line three large sheet pans with a piece of parchment paper.
Stir together the soy milk and apple cider vinegar to create vegan buttermilk. Set this in the fridge to rest while you gather together the rest of the ingredients.
In a large-sized mixing bowl, whisk the flour, baking powder, nutritional yeast, and salt.
Break the one cup of cold vegan butter into chunks and toss it into the flour mix.
Now, rub the butter and flour mix in between your hands until there are no large pieces of butter showing, and the final texture resembles a fine meal.
Create a hole in the middle of the dry mix and pour the vegan buttermilk into it. Quickly stir everything together until just combined. Do NOT over stir, or you will create chewy biscuits. The dough will be fairly sticky.
Flour your countertop and scoop out hefty 1/4 cup portions of biscuit dough. Lightly flour the dough's tops and pat them down ever so slightly. Form them into round 1-inch thick biscuit shapes. Lay the biscuits on the parchment paper-lined sheet pans 1-inch apart from each other.
Brush the tops of the biscuits with the melted vegan butter and bake one sheet pan at a time on the middle oven rack for 12 minutes. Hold the rest of the sheet pans of dough in the refrigerator in the meantime, and then you can bake them when the other pan is finished baking.
Straight from the oven, brush them with more vegan butter.