In a bowl, combine garlic, soy sauce, oyster sauce, honey, mirin, black pepper, and onion powder. Mix well and set aside.
Heat a drizzle of oil in a large skillet or cast iron pan over medium heat. Add sliced onions and sauté until translucent and slightly golden.
Move the sautéed onions to the center of the pan. Place a bowl of cooked rice over the onions (like a little mountain).
Arrange the sliced beef around the rice.
Sprinkle corn over the entire dish and add green onions on top.
Pour the prepared sauce evenly over the beef, rice, and veggies. Add a pat of butter on top for extra richness.
Let everything sizzle until the beef is fully cooked and the sauce thickens slightly. Mix everything together before serving, or enjoy it hot straight from the pan!