Coffee walnut cake

• 4 oz (100 g) self-raising flour
• 1 level teaspoon baking powder

Heat the oven to 350°F (180°C) or gas no. 4. Grease two 7 inch (17.5 cm) sandwich cake tins and line the bases with greased greaseproof paper. Sift the flour and baking powder into a mixing bowl. Add the s