Hamburger steak had become a classic Japanese dish despite being introuced to their cuisine only a short time ago. Nonetheless, it's one of those basic recipes that appears in anime all the time, and every Japanese kid seems to know how to make.
1. Caramelize half of the onion. Dice it, and then in a pan on low heat, sauté onion in a bit of olive oil until nicely browned and sweet, about 20 minutes. Set aside.