Heat a wok or deep pan over medium heat and dry roast the mushrooms for about a minute until their natural fragrance is released. Add the chopped or crumbled Taiwanese sausage and cook, breaking it into small pieces. Continue sautéing until the sausage renders its fat and develops a slight char on the edges, deepening its smoky, savory flavor.

Stir in the ginger garlic paste, sliced onion, and green onions. Cook, stirring frequently, until the onions soften and their sharpness mellows into a sweet, aromatic foundation.

Incorporate the chopped cabbage into the wok, followed by the salt, white pepper, and oyster sauce. Stir well to evenly coat the vegetables in the seasoning. Cook for about a minute, allowing the cabbage to soften slightly while still retaining a bit of crunch.

Pour 2½ cups of water into the wok and increase the heat to high, bringing the liquid to a rolling boil. Once boiling, add the rice noodles and shredded carrots. Reduce the heat to medium and cover with a lid to create a steaming effect. Occasionally lift the lid to stir the noodles, ensuring they evenly absorb the broth and soften. Allow the mixture to cook for about 6 minutes.

Taste the noodles. If they seem too firm or dry, add another ½ cup of water and continue steaming with the lid on. Adjust the seasoning with additional salt or white pepper if needed. Once the noodles reach the desired texture and absorb most of the liquid, remove from heat and serve immediately.