Chill the steak in the freezer for 10-15 minutes for easier slicing.

Thinly slice the chilled steak against the grain into strips.

Prepare the stir-fry sauce by combining soy sauce, cornstarch, sake (or white wine), oyster sauce, and mirin in a small bowl; mix until smooth.

Heat butter in a large skillet or wok over medium-high heat until it foams and lightly browns.

Add steak in a single layer (cook in batches if necessary to avoid overcrowding) and stir-fry for about 3 minutes per side, until browned and crispy at the edges.

Remove the cooked steak from the skillet and set aside.

Add sliced bok choy, chili pepper, and minced garlic to the same skillet.

Stir-fry for 2 minutes to begin cooking the bok choy.

Pour the prepared sauce over the bok choy mixture.

Reduce the heat to medium-high and return the steak, white parts of the scallions, and drained baby corn to the skillet.

Stir everything together to combine, ensuring the steak and vegetables are coated in the sauce.

Taste and adjust seasoning, adding more soy sauce if desired.

If the sauce becomes too thick, add a splash of water to thin it to the desired consistency.

Serve the stir-fry immediately over hot cooked white rice, garnished with the green parts of the scallions.

Enjoy the Steak and Bok Choy Stir-Fry.