Prepare the broth by boiling kelp and anchovies.

Place tofu in a pot and add 2 cups of broth. Add more broth if the liquid reduces too much.

Mix the seasoning ingredients well and add to the pot.

Add onions and simmer until well cooked.

Simmer on medium heat until the tofu absorbs the seasoning and the broth thickens.

Adjust the seasoning with fish sauce or salt to taste.

Push the tofu to the sides of the pot to create space in the center.

Add udon noodles and cook together until the noodles absorb the broth.

Add green chilies and green onions, then simmer briefly.

Add more broth if needed and simmer until the dish is ready.