Maybe in the future if you will add more sushi type.

I have some idea.

If you can make a "hangiri" or "flat-bottomed wooden tub"

You can make the sushi rice with some step

Add rice to the tub, add water, wash, add water, cook it. <It can be used multiple time, can make vinegar item too if you willing to create more.

Then for the nori, you can make it an item that doesnt need any preparation.

Then you can make the ingredient to be lots and with a simple step

for example:

The Maguro one, you can use tuna and chop it, and combine with the sushi rice. (same with other meat one.

Uni, interact with the urchin, and combine with the sushi rice, if you are willing to create more, maybe make a trash item (the urchin left over)

Ebi, Kani, Ika, same as above

Ikura, take the sushi rice, add nori, add the roe.

Tako, take the squid to the pot, boil, cut, add nori.

and last is my fav, the egg. take egg, mix (interact), fry, add sushi rice, add nori.

with this recipe, you can just make a lots of sushi with maybe a same code.
Also if this can be created it will fells like more like making lots of pie.

also i want to make a rotating sushi restaurant.

Note: idk, how to mod this game, maybe this will be hard or maybe not or maybe you already have planned it, just saying...