Suihanki Shoujo Komeko

From MangaHelpers:

Takeru is a poor college student, living alone. One day, his mom sends him a strange package; it's a rice cooker in the form of a young girl! She cooks the rice inside her head, but Takeru will have to get along with her in order to get her to cook rice properly. This 4-koma manga features Takeru's life with his rice cooker girl, called "Komeko," and the other girls in his life. [tethysdust]