Mix the gyudon sauce with dashi stock in a medium sized saucepan; bring to boil on medium high heat.
Add the onions to the stock and simmer for 2-3 minutes until soft.
Add thinly sliced beef and cook for 30 seconds or until cooked to your liking.
Serve over rice. I like to add a soft boiled egg and Japanese pickled ginger!
Video
Notes
Beef - It is key that you get thinly sliced beef! When making this dish, I will purchase the pre-sliced beef from my local Japanese grocery store - it's labeled as 'Kiriotoshi'. If you are buying this from your local grocery store, you can use ribeye or chuck roll - ask your butcher to slice them for you at the thinnest setting (or 1/8").Mirin - You can sub mirin with rice vinegar - but since this recipe has so few ingredients, I highly recommend you use mirin.Sake - You can sub sake with another dry cooking wine (such as white wine or sherry) - but since this recipe has so few ingredients, I highly recommend you use sake.Watch Your Sauce! - The Beef Gyudon sauce should be thick and syrupy - however, keep an eye on it as it reduces, as the sugar can lead to burning.Optional Garnishes - Top your Beef Gyudon with an egg (sunny side up, soft boiled, or a Ramen Egg and Japanese pickled ginger. I also top with kimchi when I don't have pickled ginger at home.Storage - Gyudon Sauce - You can store this is an airtight container in the refrigerator for up to 1 week. Cooked Beef Gyudon - Store any leftover Beef Gyudon in an airtight container in the refrigerator for up to 3-4 days. Reheat in the microwave or in a pan.