i would assume in the micro you would do it very similar to the oven baked one...obviously a microwaveable bowl...add a couple of tblspoons milk to the sponge...cover with cling and make a tiny hole in the top...microwave time for sponges is only about 4 mins so dependent on your microwave strength it may take some trial and error there...maybe try a couple of normal microwave sponges 1st to see how long your's takes

we did this at school and was so quick and easy but i cant remember the receipe. have looked on google and are all oven baked.