Bake a 15cm long sweet potato in the air fryer for 20 minutes, then flip and bake for another 10 minutes. It's done when a chopstick easily pierces through it.
Mash the sweet potato in a bowl.
Add egg yolks to the mashed sweet potato.
Put the egg whites in a separate bowl and make meringue. It takes about 5 minutes with a semi-automatic whisk. A firm meringue is fine, but a runnier, flowing meringue also works.
Mix all ingredients together.
Grease a microwave-safe container generously with olive oil, cover with plastic wrap, and poke holes with a chopstick. (Since the contents expand with heat, fill only up to 90% of the container.)
Microwave for 5-6 minutes (reduce time if using less batter).
Turn the container upside down onto a cutting board; if the bread comes out easily, transfer to a plate and enjoy.