Place the 6 tablespoons in a freezer-safe dish and chill in the freezer for 20 minutes.
In a glass liquid measuring cup or bowl, whisk together the soymilk and apple cider vinegar and allow to rest for 10 minutes. After 10 minutes on the counter, place in the refrigerator until ready to use.
Preheat the oven to 425 degrees F and prepare your baking sheet with a silicone baking mat or parchment paper.
In a large bowl, thoroughly combine the flour, baking powder, sugar, and salt.
After 20 minutes, add the frozen vegan butter to the dry flour mixture and use a fork (or pastry cutter) to mix it in until it looks like a crumbly mixture.
Pour the soymilk mixture into the bowl and mix together by hand. Be careful not to overmix.
Add a handful of flour to your surface and spread it around. Using your hands, spread out the dough. Fold it in half, then fold it in half again, and then stretch it back out. Repeat this four times. If the dough is sticking, add a little more flour
Spread the dough out about 1 ½ inch thick and use a round cookie cutter (or a cup that’s about 2 ½ to 3 inches wide) to stamp out biscuits and add them to the prepared baking sheet.
Bake in the preheated oven for 12 to 14 minutes, until they’re lightly golden. Cool for 5 minutes.
For the gravy: Start by either boiling or microwaving the water and bouillon cube until it's a well-combined broth, then set it aside.
In a small pot over medium-heat, add the vegetable oil and onions and saute until the onions become translucent tender. Lower to a simmer, add the flour, and stir until your roux has a smooth consistency.
Add the broth, salt, and pepper, and stir over low heat until it thickens.