Beat the egg in a bowl and add the remaining ingredients - excluding the wild berry jam.
Stir well to obtain a smooth mixture.
Finally add the wild berry jam slowly as well.
Pour the mixture into a suitable cup, filling it 2/3 up.
The ingredients listed above are for 1 cup.
Put the cup in the microwave at max setting 900w for 90 sec.
Don't open it for about 5 min., then open the oven door and take out the cup.
If it's still doughy, return to the oven for another 20 sec. because every egg size is different, as is every microwave.
Serve the cake in the cup and optionally add additional jam on top.