Grease 4 straight sided microwavable cups, put 1 tbsp jam in base of each cup. in small bowl melt butter. Add sugar and egg to a bowl with the melted butter. sift in the flour and baking powder mix well adding with the 1/2 cup milk.
put mixture evenly in mugs, (it shouldn't come to the top of the mug, as it rises when cooked). Microwave for 3-4 1/2 minutes. Run knife round the edge of cups.
Tip into a serving bowl, leave to stand for one minute then, voila, bon appetitte.