Peel and chop the potatoes, soak them in cold water briefly. Pat dry the beef with a paper towel and cut into bite-sized pieces. Dice the onion and carrot.

Prepare the seasoning sauce by mixing soy sauce, mirin, sugar, water, and corn syrup in the specified amounts.

Heat a pan with a small amount of cooking oil and stir-fry the beef until 90% cooked. Remove the beef and set aside.

In the same pan, stir-fry the potatoes, onion, and carrot for about 2 minutes.

Pour the prepared seasoning sauce into the pan, reduce the heat to low, and cook the potatoes until partially tender.

Add the pre-cooked beef to the pan and stir to coat it with the sauce. Cover and simmer until the potatoes are fully cooked and the sauce thickens.