Preheat oven to 180 degrees C. Grease and flour a lamington tin - approx 25x20cm.
In a large bowl, stir together the flour, cocoa, sugar, bicarb soda and cinnamon. Add the butter or margarine, oil, water, milk, eggs and vanilla, mix until smooth. Spread evenly into the prepared pan.
Bake in the preheated oven for 25 to 30 minutes, or until a toothpick inserted into the cake comes out clean. Allow to cool.