Preheat the oven to gas 4 / 180C / 350F and grease & line a 9" 13" ovenproof dish or tin
Dump the flour, xantham gum if using, sugar and baking soda into the tin and mix together
Make 3 large wells in the flour. In 1 put the oil, in another the vinegar and in the 3rd the vanilla
Pour the water over the whole thing and mix with a fork until the batter is combined
Bake for 45 minutes or until a toothpick tests done
You can use 2 x 8" round tins baked for around 35 minutes or 24 cupcakes will take around 25 minutes
Either let cool for 10 minutes in the tin then serve squares as dessert with custard or turn out gently and let cool completely before frosting
