Naruto and his son, Boruto, could be main characters. Boruto might not understand his father's love for the ramen shop at first, but as the story progresses, he comes to appreciate it. Another character could be Shikamaru. He might be there to relax and have some ramen while also using his intelligence to solve any problems that arise in the shop, like a sudden shortage of ingredients.
One possible plot could be that a new and mysterious ingredient is discovered in the Naruto world. This ingredient is added to the ramen in the shop, and it gives those who eat it special powers. Naruto and his friends then have to protect the ingredient from villains who want to use it for evil.
It could be a fanfiction that focuses on a character in Naruto experiencing withdrawal symptoms related to ramen. Maybe Naruto himself is deprived of his beloved ramen for some reason and the story explores how he copes.
Naruto could use his shadow clone jutsu to multitask in the kitchen. One clone could be chopping vegetables, another boiling the broth, and he himself could be preparing the noodles. His speed and agility from being a ninja would also help him serve customers quickly.
In the Hidden Leaf Village, a ramen eating contest was announced. Naruto was the first to sign up. As the contest began, Naruto grabbed a huge bowl of his favorite miso ramen. He slurped it down with great gusto, his cheeks puffed out like a chipmunk. His friends cheered him on. Sasuke watched with a smirk, secretly impressed by Naruto's appetite. In the end, Naruto won by a landslide, his stomach full but his spirit even fuller.
One interesting Naruto ramen fanfiction could be about Naruto opening a ramen chain across the ninja world. He uses his popularity and his love for ramen to bring people together over bowls of delicious ramen.
One possible plot could be that Naruto discovers a new secret ingredient for his favorite ramen. This ingredient could be a rare herb only found in a hidden part of the forest. He then tries to convince Teuchi, the ramen shop owner, to use it in the ramen. Along the way, he has to face off against some ninjas who also want the herb for their own purposes.
Perhaps a ninja who has a grudge against Naruto because he once ate all the ramen at a festival, leaving none for the ninja. So this ninja decides to target Ichiraku Ramen and tries to put a curse on the ramen that would make anyone who eats it sick. Naruto has to figure out how to break the curse and stop the ninja.
Naruto is most likely to be the main character since it's about his ramen withdrawal. But his friends like Sakura and Kakashi might also be important as they could be the ones trying to help him or dealing with his mood swings due to the withdrawal.