What is the ruling on a Muslim eating food cooked by a disbeliever who does not belong to a heavenly religion, knowing that the ingredients of the food are permissible (halal)?

There is no legal impediment to eating food prepared by a non-Muslim if its ingredients are permissible (halal). It is permissible to eat what a disbeliever has cooked, even if they are not from the People of the Book. The consideration for food containing meat is the religion of the one who slaughtered the animal.

If the non-Muslims are from the People of the Book (Jews or Christians), there is no objection to eating their food, as long as it does not contain anything forbidden (like pork or carrion), based on the Almighty's saying: (The food of those who were given the Scripture is lawful for you).

As for those who are not from the People of the Book, it is not permissible to eat meat they have slaughtered themselves, but it is permissible to eat their permissible food. It is more prudent for a Muslim to avoid eating anyone's food if there is no hardship in doing so.

There is no objection to eating with non-Muslims in a restaurant if the food ingredients are permissible, as the consideration is for the ingredients and not the religion of the one who prepared the food.