Using a medium saucepan, heat 2/3 cup water until boiling, then add your oats. Don't put the lid on and make sure to frequently check on your oatmeal and give it a stir so it doesn't boil over.
Once the oats have absorbed that initial 2/3 cup of water, add another 1/3 cup of water. They can actually still absorb a little bit more water (to be even more voluminous) if you add it in two batches like this!
While the oats are cooking, put your banana into a bowl and mash it with a fork. When the oats have absorbed that second batch of water, add the mashed banana, vanilla, and cinnamon. The banana will caramelize as it cooks, maximizing the sweetness without requiring any added sugar! Just stir frequently to make sure the banana doesn't burn.
Grate your zucchini directly into the pot using a microplane, so its as fine as possible. If you aren't too keen on the color green being in your finished bowl, you can peel the squash first so that it doesn't add any color.
While the mixture is heating up again, separate two egg whites from their yolks and beat in a bowl until very frothy. Bonus: arm workout included in your breakfast making!
Once your oatmeal starts to bubble, pour your frothy egg whites in and mix thoroughly. If you're cooking at medium to medium-high heat, it should only take a minute or two for your egg whites to cook - you'll want to be stirring pretty constantly this whole time to prevent clumping. If you've done it right, the egg whites will easily incorporate to the rest of the mixture, resulting in a thick, puffy, cloud-like consistency. No lumps at all!
Finally, pour into a bowl and top with a little bit more cinnamon plus a few chocolate chips. I like to use the mini ones so they melt faster and spread through the oatmeal! If you wanted to make this healthier, you could substitute cocoa powder or even go without... but who doesn't want a bit of chocolate to start their day? :)