Preheat the oven to 180C. Grease a 20cm cake pan. Because the batter is quite liquid a springform pan isn’t suitable here.
In a large mixing bowl, whisk together the dry ingredients.
In another mixing bowl, combine the milk and acid and leave it for a few minutes to curdle. Add all the remaining wet ingredients except for the boiling water and whisk to combine.
Add the dry ingredients to the wet and whisk until the batter is smooth. It should feel lightly aerated under the whisk.
Pour in the boiling water and whisk to combine. This will bloom the cocoa and gelatinize the starches in the flours, helping hold the cake together.
Once the batter is smooth and the water is totally incorporated, pour the batter into the greased pan and place In the oven for 30-35 minutes. Allow it to cool in the pan for 15-20 minutes before gently tipping it out onto a cooling rack.
Because this is an oil based cake, it keeps well on the counter for a few days. The cake can also be frozen. Allow to cool completely before icing.