Cook the sauce. In a small saucepan over medium heat, add the sake, mirin, soy sauce, and sugar. Bring to a boil, then simmer for 2-3 minutes.
Cook the onions and beef. In a deep skillet, heat 1 tablespoon of oil over medium-high heat until hot, then sear the onions until softened, about 1-2 minutes. Then push to one side and sear the beef on both sides for about 1 minute.
Simmer in the sauce. Pour half the sukiyaki sauce and simmer for 1 minute.
Add the vegetables. Next, arrange the tofu, shiitake mushrooms, enoki mushrooms, shimeji mushrooms, carrots, napa cabbage, chrysanthemum greens, shirataki noodles, and green onions in the pot. Then pour in the dashi broth and the rest of the sukiyaki sauce. Cover and simmer until the veggies are tender, about 10 minutes.
Serve. Serve with white rice. Enjoy!
Notes
If using dashi powder, use 1 teaspoon of dashi powder per 1 cup of boiling water.
See the What I Learned Testing This Recipe for more guidance.