Preheat the oven to 350°F (175°C). Line two cupcake pans with cupcake liners.
In a small bowl, mix the soy milk with the apple cider vinegar and set aside for 10 minutes to thicken. It may look a bit separated at this point, but that’s normal.
In the bowl of a stand mixer fitted with the paddle attachment, mix together the flour, sugar, baking powder, baking soda and salt until combined.
With the mixer turned off, add the soy milk mixture, vegetable oil and vanilla extract. Mix on low speed until a smooth batter forms, 15 to 30 seconds, scraping down the sides of the bowl as needed.
Using a large retractable ice cream scoop, divide the batter evenly between the prepared cupcake liners. Bake for 18 to 22 minutes, until the cupcakes have a gently rounded, golden-hued dome, and a toothpick inserted into the centre comes out with only moist crumbs.
Let the cupcakes cool completely in their pans set on top of wire racks.