In a wide, shallow bowl, beat egg, milk, cinnamon and salt together with a fork. Dip bread slices in egg mixture, one at a time, making sure to soak each side.
Melt some butter in skillet over medium heat. Add slices of bread onto the skillet as will fit at a time.
Fry until brown on both sides, flipping the bread when necessary.
Serve hot with butter and maple syrup.