Separate the egg, putting the white and yolk in separate bowls. Mix the egg yolk with the flour, baking powder and milk to make a smooth paste.
Beat the egg white and a pinch of salt with an electric whisk (or by hand) until fluffy and holding its shape. Gently fold the egg white into the yolk mixture. Be extra careful not to knock any of the air out.
Heat the butter and oil in a non-stick frying pan. Dollop a third of the mixture into the pan and cook on each side for 1-2 mins or until golden brown. Repeat with the remaining mixture to make three pancakes. Drizzle over some maple syrup or honey and serve with berries, if you like.