Whisk the apple cider vinegar and salt into the soy milk. Return to the refrigerator so it's very cold.
Measure and then cut up the vegan butter and put in a freezer-safe bowl in the freezer while you measure the flours.
Weigh the flours into a medium-sized bowl, or gently spoon or sift the flours into the measuring cup, leveling off with the flat blade of a knife.
Add to a medium-sized bowl and whisk together until it is a uniform color. Add the rest of the dry ingredients. When you measure the baking soda and baking powder, use a fine sifter or wire mesh to remove any possible lumps. Whisk again until thoroughly mixed.
Cut in the frozen butter using a pastry sieve or two knives in a cross-wise pattern until the butter is reasonably well mixed in and about the size of aquarium pebbles (or small peas).
Return the bowl to the refrigerator for ten minutes.
Turn on the oven to 425F/220C/gas mark 6.5. The oven should be preheated in about ten minutes.
Scoop the dough (if it is not scoopable, let it stand another five minutes to set up) onto a parchment-covered baking sheet using an ice cream scoop or large spoon.
Bake for 11 minutes or until golden brown and lightly cracked on top.
Serve immediately for best flavor and texture. Store for a day in a zippered bag, or in the freezer. Reheat in a 300F/150C/gas mark 2 oven for 10-15 minutes, not in the microwave.
Notes
Per serving:
141 calories
5 g fat
0 g cholesterol
329 mg sodium (182 mg sodium with salt omitted)
31 mg potassium
22 g carbohydrate
1 g fiber
1 g sugars
2 g protein
4 Weight Watchers Points Plus
Since it took me six tries to make these, do not make any substitutions in this recipe. If you want biscuits, get these flours. Do not omit that tiny little teaspoon of psyllium husk fiber. It is essential for creating the dough structure. Unfortunately, soy milk is the only non-dairy milk that curdles properly, so I can't suggest a substitute for you non-soy people.With that said, you can try to reduce sodium further by using low-sodium soy milk (some are as low as 15 mg per cup, some are as high as 180 mg), use unsalted vegan butter if you can find it (or make it yourself using this recipe). This should bring the total down to about 125 mg per biscuit. I have not tested this recipe with these changes, so I can't be certain it will work.