This is pizza toast I've been making for ages. If you have bread, egg, cheese, and mayonnaise, you could easily make this toast!
My late mother used to often make this for our breakfast or a lunch on a day off when I was a child.
You can also cut the bread into smaller pieces. Don't under-cook the eggs, but also be careful not to cook for too long or it will become like tartar sauce when you combine with the mayonnaise.
Enjoy Japanese food around the world.