Partner ~Sekai de Ichiban Taisetsu na Hito~

Main character is a teacher who gets to know one day that he is very popular among girls.

Erika is anxious to astonish him with culinary skills.

Natsuki keeps her grades up and involves teacher in serious talks about future career.

Sakaki is an artist who feels joy after being praised by the teacher.

[From vndbreview]