Adjust your oven rack so it’s in the middle position and preheat to 425°, and lightly oil a 9 or 10-inch baking pan.
Clabber the soy milk by combining it with the apple cider vinegar in a small bowl. Allow the mixture to sit for 5 to 10 minutes.
Combine the flours, baking soda, and salt in a large bowl, and whisk to combine.
Add the clabbered soy milk to the dry ingredients, and mix with a wooden spoon until just combined. The mixture will be sticky.
Scrape the mixture into the prepared baking pan, and bake for approximately 35-45 minutes, until the bread has risen and is golden brown. You can use a sharp knife to cut a large X into the bread after about 15 minutes, if you like.
Place the pan on a cooling rack for 10 minutes. Carefully remove the bread from the pan, and place on the cooling rack and allow to completely cool before slicing