Prep the ingredients: Cut the napa cabbage into bite sized pieces. Slice the green onion and shiitake mushrooms. Gently slice the tofu, onions and green onions.
Cook the vegetables: Add all of your preferred ingredients into a large pot. Add water and cover with a lid. Bring to a boil and then cook for 3 to 4 minutes until the cabbage wilts and the mushrooms are tender.
Make the broth: Turn the heat to medium low. Add the dashi powder and stir until it dissolves. Using a ladle of the hot broth, gently whisk in the miso paste until it is fully mixed.
Udon and beef: Gently add the frozen udon and thinly sliced beef to the pot. Push the beef into the broth so it cooks through in the hot liquid. Pour in soy milk and mix with broth. Cover with lid and cook for 2-3 minutes.
Add the udon: Add the Frozen udon to the pot and stir gently. Cook according to the package instructions or until the udon is heated through and tender, usually 2 to 4 minutes.
Finish and season: Taste the broth and adjust seasoning if needed. If it needs more depth, add a little more miso paste or a splash of soy sauce.
Serve: Ladle the hotpot into bowls with plenty of udon, vegetables, beef, and tofu. Garnish with sliced Green onion. Enjoy!