Combine oats, water, and salt in a bowl. Beat the egg white, then whisk it in with the uncooked oats.Microwave for 2 minutes (or boil on stovetop). Check consistency and continue to heat as necessary until the oats are fluffy and thick.Thaw banana, mash, and add to oats. Heat another 30 seconds in microwave.Stir in flax, brown sugar, and cinnamon. Top with peanut butter!