Make the warishita: combine soy sauce, mirin, sake and sugar in a small pot. Bring to a simmer, stir to dissolve the sugar, and set aside.
Heat a cast iron or heavy pan at the table or stove. Grease lightly with oil or tallow.
Sear the beef slices in batches over high heat for about 30 seconds per side. Push to the side of the pan.
Arrange the tofu, shirataki noodles, spring onions, cabbage and mushrooms in the pan alongside the beef.
Pour the warishita over everything. Simmer for 5–8 minutes until the vegetables are just tender and the broth has reduced slightly.
Serve directly from the pan. Traditionally, each piece is dipped in raw beaten egg before eating.