Mai-chan no Oneesan Shiiku Gohan.

In a town where the train only comes a few times a day, where there's scarce entertainment, where there's only one local supermarket and rice paddies as far as the eye can see, in such a rural town, one day Mai, an elementary schooler who lives with her father, has a fateful encounter with a fallen beauty. With blonde hair and wearing a sailor uniform, the girl looks as if she was a princess straight out of a picture book... but, in reality, she can barely feed or clothe herself, not to mention that she's in serious need of a bath. What's more, she's uncommunicative and socially inept—truly a lost cause. Unable to just watch, Mai begins to take care of the girl and cook homey meals for her. Using her small hands, Mai provides the mysterious beauty with a taste of a mother's cooking. Her maternal inclinations tickled from the charm and hopelessness of the girl, Mai thinks to keep her as a pet...?! A motherly elementary school student seeks to understand and tame this NEET-like high school girl in this cute gourmet comedy.

(Source: Takeshobo, translated)