Pre-heat the oven to 220°C/425°F/Gas mark 7. Mix the two flours together with the baking powder, sugar and salt. Then break in the egg and add the milk and oil to make a batter. Beat thoroughly using a whisk or an electric beater. Grease a bun tray or muffin pan and pour the batter into each space. Sprinkle with the sesame seeds and bake for 20 minutes, or until the muffins have risen and browned. Turn on to a rack and leave to cool.