Mince the onion and microwave it in a heatproof container covered with plastic wrap for 1 minute at 600W. Let it cool.

In a bowl, mix breadcrumbs and milk until absorbed. Add ground meat, onion, salt, and pepper, then mix and shape into a heart.

Heat salad oil in a pan over medium heat. Cook the hamburger steak until browned, flip, cover, and cook on low heat for 7 minutes. Remove and blot excess oil.

Add the teriyaki sauce ingredients to the pan and simmer on low heat until thickened. Coat the hamburger steak in the sauce.