Prepare the ingredients as shown. Soak the hot and sour soup mix in 1/2 cup water; it won't fully dissolve, but will blend in when cooking.

Slice the onion thinly. Cut the potatoes and tomato into bite-sized chunks. Finely chop the green onion.

Heat oil in a pot. Sauté the sliced onion and the white part of the green onion until fragrant. Add the meat slices and cook until they change color, then add the potatoes and tomato and continue to stir-fry.

Add the tofu and shimeji mushrooms, then pour in 1/2 cup water. Cover and simmer.

Once the potatoes are tender, pour in the soup mix water and gently stir to combine. Add the kimchi, taste and adjust seasoning as needed. You can add pepper or vinegar to taste. Sprinkle with chopped green onion, then turn off the heat.