1. Thinly slice beef ribeye round. If you stick it in the freezer for about 30 mins to an hour, it will be easier to slice thin. Or just by it pre-sliced, like I do (Korean grocery stores typically carry this or I've even asked the butcher at my local grocery store to do this for me).
2. Next make the marinade by mixing the remaining ingredients together.

3. Pour the sauce into the dish with the beef and mix into the layers well.

4. Let the beef marinate in the sauce in the fridge for at least an hour. I've also let it sit overnight.

There are many ways to cook this:

1. My favorite way is on the grill, on a layer of aluminum foil.
2. You can also bake/broil it in the oven layed flat on a lightly greased roasting pan or baking dish. In an oven, I usually broil it at 400 degrees for about 15-20 mins until its cooked through and edges browned. Be sure to keep an eye on is as ovens vary.
3. Or simply sauté it up in a couple batches on the stove in a pan with a little oil until cooked through.