Sauté the aromatics: Heat the neutral oil and sesame oil in a large pot over medium heat.
Add onion with a pinch of salt and cook 4–5 minutes until soft. Stir in garlic and ginger (and turmeric if using). Cook 1 minute, just until fragrant.
Build the broth: Pour in the broth.
Add soy sauce or tamari, rice vinegar, and chili crisp or flakes if using. Bring to a gentle simmer.
Add mushrooms and tofu: Stir in mushrooms and tofu. Simmer 5–7 minutes until mushrooms are tender.
Cook the noodles: If using udon or soba, you can cook them directly in the pot until just al dente.
For rice noodles, cook separately per package to avoid cloudy broth, then rinse and hold.
Finish with greens: Add the greens and green onions. Simmer 1–2 minutes until just wilted but still bright.
Stir in miso off heat: Turn off the heat. Ladle a cup of hot broth into a bowl and whisk in the miso until smooth.
Return that mixture to the pot and stir. Taste and adjust with more miso, soy sauce, or a touch of honey.
Assemble and serve: Divide noodles among bowls if cooked separately. Ladle over the miso-ginger broth with veggies and tofu.
Top with sesame seeds, nori strips, cilantro, and a squeeze of lime.