Preheat the oven to 375°F/190°C (170°C for fan oven), and grease a 13x9 inch cake pan. Set aside.
In a bowl, combine the dry ingredients.
In a separate bowl, whisk together the sugar, eggs, vanilla, oil, and milk.
Add the dry ingredient to the wet ingredients, then mix to just combine (do not overmix, you don't want to work the gluten for a moist cake).
Stir in boiling water, this will thin out the batter.
Pour the batter into the prepared pan, and bake for 30-32 minutes or until a toothpick inserted in the center of the cake comes out clean.
Allow the cake to completely cool then poke holes over the top using a handle of a wooden spoon.