Combine mirin, soy sauce, water and sugar in a small sauce pan and bring it to a boil. Once boiling, turn off the heat and set aside.
Cut the ribeye steak into paper-thin slices (or most Asian grocery stores have pre-sliced beef for sale).
Brush off any loose dirt on the enoki mushrooms with a paper towel, cut off and discard the roots, tear into smaller bundles and set aside.
Cut tofu into ½-inch slices and slice the carrot.
Separate the nappa cabbage leaves from the stem, rinse them under water and set aside.
Place and arrange all the ingredients in a Japanese clay pot or a cast iron pot and pour the broth into the pot.
Cover with a lid and bring to a boil under medium-high heat.
Once boiling, turn to low heat, simmer (with lid on) for another 15-17 minutes until all ingredients are cooked through.
Sprinkle with chopped scallion to serve and enjoy!
