Budget Pantry Fudge Cake

1 1/2 cups self-raising flour
3 tablespoons cocoa
1 cup sugar
1 cup water
1 teaspoon vanilla essence
1 tablespoon white vinegar
6 tablespoons vegetable oil (not olive or other strong flavoured oil)
1/4 teaspoon salt
1/4 cup sugar (optional)

Icing:
1 cup sugar
1 1/2 tablespoons cocoa
1 tablespoon butter
2 cups hot water

Heat oven to 350F.
Grease and flour a 20cm round tin.
Place all cake ingredients (except icing sugar) into a bowl and whisk until smooth.
Pour into prepared tin and bake 35-40 minutes. Remove from oven and cool in tin for 10 minutes before turning out.
When cool, either dust with optional icing sugar (vegan and dairy-free option), or top with icing.
To make icing, combine sugar, cocoa and butter, then add small quantities of hot water, stirring vigerously, until icing consistency is as you like it.