Dice soy fish and button mushroom into desired size. I like it small so it kinds of stick on the pasta when I eat it, but some might like it in bigger chunks if you want something biteable on the sauce.
Stir fry soy fish and button mushroom bits/chunks on butter until lightly brown. Sprinkle also with black pepper and Italian seasoning.
Lower the fire to minimum heat and pour in the all-purpose cream. Immediately season with vegetarian chicken powder (VCP) and more Italian seasoning.
Mix the sauce well to avoid burning the cream, especially the ones on the circumference of the sauce.
Before the sauce boils, add in 3/4 of nori (cut into confetti size) and adjust taste. If saltiness of nori is not enough for your tastebuds, this is the time to add some salt.
Turn the fire off but keep on mixing for a few more seconds.
Top your spaghetti with this sauce and sprinkle the rest of the nori confetti on top.
Tips and tricks Some people don't like too creamy white sauces so you might want to dilute your sauce with water or fresh milk. Add it right after pouring in the cream and while mixing, to keep track of your sauce's consistency.
While some people don't like it too creamy, some people like it even creamier. My tips is to add grated cheese into the sauce and decrease or remove the salt.