Preheat oven to 350° F (177° C). Lightly grease an 8" square (20x20x5 cm) or 9" (23 cm) round pan (the pan needs to be at least 2" (5 cm) deep)
In a medium bowl, whisk the dry ingredients together. In a separate bowl, mix the vanilla, vinegar, vegetable oil and water. Pour the wet ingredients into the bowl of dry ingredients and stir until thoroughly combined. Pour the batter into the prepared pan.
Bake the cake for 30-35 minutes, until a toothpick inserted into the center comes out clean, or with a few moist crumbs clinging to it.
The cake is very good without frosting, but you can also add a frosting if you want.
To add frosting: Once the cake has cooled, heat the chocolate chips with the non-dairy milk until the chips melt. Stir until smooth, and pour/spread over the cake.
Store cake, well covered, in the refrigerator for several days; freeze for longer storage.