Is it obligatory for a wife to cook food for her husband?

Praise be to Allah.

Shaykh Ibn Jibreen said: the custom of the Muslims has always been that the wife should serve her husband in the customary manner, by preparing food, washing his clothes and vessels, cleaning the house, etc., according to what is appropriate. This was the custom at the time of the Prophet and has remained so until the present day, and no one has objected to it. But the wife should not be burdened in a manner that causes her hardship or difficulty, rather it should be in accordance with her ability and what is customary. And Allaah is the Source of strength. 

See Question no. 10680.