Hot chocolate cups

I've made this one a couple of times. It's really nice to do if you're having the girls over for some tea... Who says no to chocolate anyway?? :D

300ml self-raising flour
150ml castor sugar
100ml cocoa powder
1ml salt
1 egg
125ml milk
50g butter, melted
3ml vanilla extract or 5ml vanilla essence
90ml soft brown sugar
250ml boiling water

Preheat the oven to 180 deg C and grease 4x 250-275ml ovenproof cups or ramekins with butter, margarine or nonstick food spray. 
Sift flour, sugar, half the cocoa powder and salt together.
Make a well in the mixture
Lightly whisk together the egg, milk, butter and vanilla essence and pour the mixture into the well. Beat slowly to make a smooth, thick batter. 
Spoon the batter into cups or ramekins, spreading the mixture evenly over the batter in the 4 containers. 
Divide the boiling water among the containers, pouring it slowly on top of the batter until the containers are three-quarters full. 
Bake for 20-25 minutes or until well risen and firm to the touch.
Serve with ice cream if desired.