Combine the flour, cocoa powder, baking powder, salt, and sugar in a bowl, and mix.
In a separate bowl, combine the vegetable oil and chilled water, then add the vinegar and vanilla essence. Preheat the oven to 180℃.
Pour the wet ingredients into the dry ingredients and mix with a whisk.
Pour the batter into a cake pan and bake for 20-30 minutes at 180℃.
While the cake is still hot, place a large bowl over the cake to steam while cooling. This will make the cake nice and moist. Once it is cool, sprinkle on the powdered sugar and serve.
Story Behind this Recipe
This is based on a recipe I found while searching for a cake for my daughter with food allergies, but the original recipe has been deleted, so I came up with my own version. My friends tell me that this is great even for those without food allergies. It's so moist and delicious. It has less calories than standard gateau au chocolat.
Depending on the rice flour you use, the amount of moisture needed may vary. The baking time may also vary depending on your oven, so adjust as necessary.