Preheat the oven to 180 degrees C
Place the flour, bicarbonate of soda, salt and sugar into the ramekin and mix well
Mix together the oil, milk and coffee and pour into the dry ingredients
Whisk to form a smooth cake batter, clean the ramekin edges and bake for 15-18 minutes until risen, lightly golden and a knife comes out clean.
Leave to cool. (At this point, if you have some coffee left it's nice to drizzle 1 tsp over the sponge to give extra flavour and keep the sponge nice and moist.)
To make the icing, whisk together the margarine, icing sugar and coffee
Spread over the cooled cake and decorate with a light dusting of cocoa powder for the cappuccino effect