Does a mother's assisting her daughter in cooking a dish that the daughter swore she would not cook constitute a breach of oath requiring expiation, knowing that most of the effort came from the daughter?

It appears that the mother would break her oath by appointing her son to cook and assist him in it, unless she intended by her oath to cook directly herself, in which case she would not break it. Ibn Qudamah said in Al-Mughni: "Whoever swears not to do something, then appoints someone else to do it, breaks their oath, unless they intended to do it themselves."