Preheat the oven to 180°C/360°F and prepare a cake pan lined with a parchment paper. Or apply oil on the base and on the sides of the cake pan with a brush and dust some cocoa powder over the top of the oil and shake it around. Make sure to cover the base as well as the sides of the cake pan. Dust out the extra cocoa from the cake pan. Set this aside and start with the ingredients.
Set this aside and start with the ingredients.In a small bowl, mix the olive oil, warm water and vanilla, then set it aside until needed.In a large bowl sift the flour together with the baking powder, and salt, mix well with a whisk.
Add in the sugar and cocoa powder and mix well.Slowly pour the oil and water mix into the dry ingredients, and gently mix with a whisk until combined and lump-free.
Pour the cake batter into the prepared cake pan and even the top using a spatula. Sprinkle some chopped nuts on the top or you can bake it without the nuts if plan to layer with cream.
Arrange the cake pan onto the middle rack and bake in the oven for about 30 - 35 minutes, then insert a toothpick in the middle of the cake. If it comes out dry, your cake is done, otherwise, continue to bake for a further 5 minutes, then check again.
Take the cake out from the oven and allow to cool completely before removing it from the pan. You can dust generously with confectioner sugar if you like, and serve.