It's more of a title hunt really. Anyway here's all the info I know:

The MC is a highschool student who works as at his parents' restaurant. One day a girl who goes to the same school as her buys some jumbo karaage out of his amazement. So he watches her eat those Karaage's and was surprised by how much she could eat. When she was paying, he noticed that she has a strip of seaweed(?) in her wallet.

Would release all the info so it could be easier to pinpoint, but I'm afraid some may be interested as well, and accidentally spoil the other chapters.

It's Mogusa-san

in need of romance?
uncommon, sad, sweet

Yep, beat me to it.

Ah! Bless you. Thank you for helping me find it again.