Mix together all of the ingredients, except the berries, to make a smooth dough. Fold in the berries.
Put nonstick paper cases in a 12-section muffin tin and spoon the mixture into the cases. Bake in a preheated oven, 180°C (350°F), Gas Mark 4, for 25 minutes or until a skewer comes out clean when inserted. Transfer to a wire rack to cool.