Using an electric whisk, mix together your dairy free margarine and sugar. 

Add the egg to your mixing bowl. Put in a tsp of vanilla extract and whisk again until well combined.

Lastly, add the gluten free self-raising flour and whisk for one last time until you're left with a nice, smooth mixture.

Grab a microwaveable bowl - mine is a tiny ceramic pudding basin about 5cm wide. Grease it by spreading a thin layer of dairy free margarine all around the inside of it. I do this with some kitchen roll. Then spread a nice, even layer of jam around the inside of the bowl - don't use too much!

Fill your bowl with your cake mixture up to half-way full. It'll rise a lot, so you'll need to leave the extra space or it'll overflow when cooking.

Place your bowl onto a plate to catch any that might overflow. Then cover the bowl with another plate and microwave on full-power (900W) for 1 and a half minutes if you're using a small pudding basin (about 5cm in diameter). Or between 2 to 2 and a half minutes in an average-sized cereal bowl.

Enjoy!