1. Preheat oven to 180°C/350°F/Gas 4. Lightly grease a 19cm/8" round cake tin and line the base with greaseproof paper.
2. Put the flour and sugar into a mixing bowl, sieve in the cocoa powder and bread soda and mix well.
3. In a small bowl, beat the oil, vinegar, vanilla essence and water.
4. Add the liquid to the dry ingredients and mix until well blended. Immediately transfer to the prepared tin.
5. Bake for about 40 minutes until firm to the touch and well risen.
6. Allow to cool in the tin for about 15 minutes, then transfer to a wire tray. Serve warm.

Note

• This is an ideal birthday cake for anyone with an allergy to dairy, eggs or nuts