Mimoza Yakata de Tsukamaete

The protagonist Haruka is a new teachter in a secondary school. She decides to settle herself in the Mimosa pension. The owner is young man who offers her a low-rent on one condition: helping to prepare dinner every evening. Haruka accepts, but is astonished when she finds out the next day that Areira, the young man, is a student of her class.

(translated from: shoujo-manga.net)