Ii Kagen na Yakushoku

Yoshino is a university student who works part-time as a house cleaner. One day, while cleaning a luxurious mansion, she ends up making midnight snack for the owner. What Yoshino makes is a sloppy risotto made with expired ingredients. However, for some reason, the owner likes it and she ends up becoming the midnight snack maker for the mansion.

(Source: Alphapolis, translated)