Preheat the oven to 350f and grease and line a large baking sheet with parchment paper. I used a 9¨ x 13¨
In a large bowl whisk together the flour, sugar, cocoa powder, baking soda, baking powder and salt.
In a separate bowl whisk together the vegetable oil, milk, vanilla and eggs then add these into the dry ingredients and mix until combined with a spatula.
Add in the hot water and whisk until you have a smooth mixture.
Pour onto the baking sheet and place in the oven for around 30 minutes until a toothpick comes out clean when inserted in the centre.
Allow to cool completed before cutting and assembling.