Bring diced beef steak to room temperature and season with salt and pepper.

Heat salad oil in a frying pan over medium heat. Add the diced beef steak and sear for about 1 minute until browned. Flip and roll the steak to brown all sides evenly. Remove from the pan and cover with aluminum foil for 5 minutes to cook through with residual heat.

In the same frying pan, add the sauce ingredients (butter, sake, soy sauce, and garlic) and heat over medium heat. Stir until the butter melts and the sauce starts to bubble.