Banana and Chocolate Mug Cake A quick and easy microwave recipe that is the definition of comfort food: banana and chocolate! Serves 1 PT2M PT4M PT6M Ingredients: 1 banana, 3 tablespoons self-raising flour, 1 egg, 1 tablespoon rapeseed oil or other vegetable oil, 2 teaspoons cocoa powder. 1/2 teaspoon vanilla essence , A pinch of salt, Instructions: 1) Put the banana into a freezer bag. Using a mallet (or your hands) mash the banana up. 2) Put all the ingredients into a microwave safe mug. Stir up until combined and put in the microwave for 1 minute. It will rise quite dramatically, but don't worry. 3) Take it out and check that it isn't ready - when it is ready it will have a solid top and be coming away from the side. If not, put back in the microwave for another minute.