Preheat the oven to 350°F/180°C
Grease and line a 9 inch (23 cm) square baking pan.
In a large bowl, combine the flour, sugar, baking soda, salt and lemon zest
Stir the vinegar into the water.
Add the vinegar and water combination, oil and vanilla extract into the flour mixture.
Whisk or beat on low speed with a handheld beater until the batter is smooth.
Pour the batter into the prepared pan.
Bake for between 30 and 35 minutes. To test the cakes for doneness, insert a toothpick into the centre of the cake. If it comes out clean, it’s done.
Turn the cake out onto a cooling rack two minutes after baking. Leaving it in the hot pan for too long will cause the middle of the cake to become soggy and dense. Cool completely before frosting.