Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.

Mash the avocado in a medium bowl until smooth and creamy.

Whisk the egg in a separate bowl until well combined, then mix it into the mashed avocado along with the shredded mozzarella cheese.

Season the mixture by adding salt and any optional seasonings like garlic or onion powder.

Shape the mixture into four equal portions and form them into ¼-inch thick rounds on the prepared baking sheet.

Sprinkle sesame seeds and poppy seeds on top if desired.

Bake for 20 minutes, or until the tops turn golden brown.

Cool the buns on the baking sheet for 10 minutes before transferring them to a wire rack.