Ruling on preparing a specific type of food for a new mother and those who come to visit her
Question

There is a special type of food that is made for the new mother and those who come to visit her to eat. This is a tradition in our country, and there is no specific belief connected to it. What is the ruling on that? Is it an innovation (bid‘ah), and how can we differentiate between customs and traditions that are permissible and innovations?
Praise be to Allah.The difference between the customs and traditions that are permissible and innovations is that the aim of the innovation (bid‘ah) is to seek to draw close to Allah, may He be exalted, by means of it. As for customs and traditions, there is no such aim behind them.
The basic principle is that customs and traditions that are practised by people are permissible, and it is not permissible to regard any of them as prohibited except on the basis of sound evidence to that effect.
Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) said:
The difference between customs and traditions, and worship is that worship is that which Allah and His Messenger have enjoined upon us for the purpose of drawing closer to Allah and seeking His reward. As for customs and traditions, that refers to what has become widespread among the people in terms of food, drink, shelter, clothing, means of transportation, interactions and so on.
There is another difference, which is that the basic principle regarding acts of worship is that they are not allowed and are prohibited unless there is evidence to indicate that they are indeed acts of worship, because Allah, may He be exalted, says (interpretation of the meaning):
{Or have they other deities who have ordained for them a religion to which Allah has not consented?} [ash-Shoora 42:21].
As for customs and traditions, the basic principle regarding them is that they are permissible, unless there is evidence to disallow them.
Based on that, if the people have a custom or practice, and someone says to them that it is haraam, he should be asked for evidence. It may be said: Where is the evidence that it is haraam? But in the case of acts of worship, if it is said to someone that this act of worship is an innovation (bid‘ah), and he says that it is not an innovation, we say to him: Where is the evidence that it is not an innovation? That is because the basic principle regarding acts of worship is that they are not allowed unless there is evidence to prove that they are prescribed."(Liqa’ al-Baab al-Maftooh  72/2).
He also said:
The guideline on innovation (bid‘ah) according to Islamic teachings is that it is worshipping Allah in a way that He has not prescribed. If you wish, you may say that it is worshipping Allah, may He be exalted, in a way that was not the practice of the Prophet (blessings and peace of Allah be upon him) or the Rightly Guided Caliphs who succeeded him. Anyone who worships Allah by doing something that Allah did not prescribe or that was not the practice of the Prophet (blessings and peace of Allah be upon him) or the Rightly Guided Caliphs who succeeded him is an innovator, whether the act of worship has to do with the names and attributes of Allah, or it has to do with the rulings and laws that He prescribed.
With regard to everyday matters that follow custom and tradition, they cannot be called innovations in religious terms, even if they may be described as innovations in linguistic terms; they are not innovations in religious terms, and they are not what the Messenger of Allah (blessings and peace of Allah be upon him) warned us against." (Majmoo‘ Fataawa wa Rasaa’il Ibn ‘Uthaymeen  2/292).
Shaykh al-Islam Ibn Taymiyah (may Allah have mercy on him) said:
People’s words and deeds are of two types: acts of worship on the basis of which their faith and religious commitment will be sound, and traditions and customs that they need in their worldly affairs. By examining the basic principles of Islamic teaching, we learn that the acts of worship that Allah enjoined or that He loves cannot be proven except on the basis of a sound religious text. As for traditions and customs, this refers to practices that people need in their worldly affairs; the basic principle regarding them is that they are not disallowed, so no custom or tradition is to be disallowed except that which Allah, may He be glorified and exalted, has forbidden." (Majmoo‘ al-Fataawa  29/16-17).
Shaykh Ibn Jibreen (may Allah have mercy on him) said:
There is a difference between acts of worship, and customs and traditions. Customs and traditions are permissible, so it is permissible for a man to build whatever he wants, to wear whatever he wants, to use whatever means of transportation he wants, and to set up whatever kind of industry or craft he wants. These things are not called innovations (bid‘ah), for there is no such thing as a worldly innovation. Religious innovations, however, are all bad and there is no such thing as a good innovation (bid‘ah hasanah) or any permissible innovation. Rather everything that has been added to Islamic teachings that is not part thereof is not permissible.
End quote from a transcribed lecture by Shaykh Ibn Jibreen
So the basic principle with regard to traditions and customs is that they are permitted, unless there is a reason to disallow them, such as if a custom or tradition involves something that is prohibited, like extravagance, wastefulness or boasting. If it does not involve any of these things, then it is permissible.
Based on the above, if this food that is prepared for the new mother and those who come to visit her does not contain anything that Allah has prohibited, and is not regarded as extravagance, wastefulness, boasting and the like, then it is permissible and there is nothing wrong with it.