Oitsukenaishi Modorenai

The story follows Hiori Naoe, the handsome 38-year-old manager of a cafe, and Mako Azusawa, the level-headed high school girl who works there part time. Mako is always chastising Hiyori for acting narcissistic, but she is secretly charmed by his good looks.
(Source: Anime News Network)
Note: Includes 2 extra chapters.