I've been doing a lot of vegan and gluten free baking lately. Instead of using an egg, I use 1 tablespoon of flax powder mixed with 3 tablespoons of water. It results in a thick and creamy liquid that simulates an egg in baking. If you have flax meal or flax seeds, put some in a coffee grinder to grind it into a powder. Remember, one egg = one tablespoon of flax powder mixed with three tablespoon of water!