Preheat an oven to 300 F. Separate the yolks from the egg whites, making sure not to let any of the yolk break (if a yolk breaks, you will need to throw out all of the whites!). The best way to separate the eggs is to crack them into a bowl and then use your hands to cup the yolks and allow the whites to fall through your fingers. Add the egg whites to the bowl of a stand mixer fitted with a whisk attachment.
Step 2
Begin whipping the egg whites until foaming. Then add the cream of tartar and the cornstarch and continue beating until stiff peaks form. To check this, stop the mixer, remove the whisk from the machine, then dip the whisk attachment into the whites and pull straight up. If a peak forms that does not fall over, then a stiff peak has been achieved. If the peak bends down, then you will need to keep beating the mixture. Add a couple of drops of gel food coloring (optional) and beat in briefly.
Step 3
Scoop the batter onto a baking sheet lined with a silicone baking mat. Shape the egg whites with a spatula until nicely rounded/domed. Bake for 20 minutes or until the outside is nicely browned and the center is cooked through.
Step 4
Allow the bread to cool on the baking sheet for 5-10 minutes as it will continue to cook and be easier to handle.