Prime Rib (プライムリブ Puraimu Ribu), according to the MOTHER Encyclopedia, is "the dinner dish that Ninten's mother prepares once-a-week" and "is Ninten's favorite."
This food restores all Psychic Points and Hit Points to Ninten and his party. However, because it is not an actual item similar to Ness' favorite food, Steak, it is impossible to obtain and can only be consumed by visiting Ninten's mother or talking to a certain NPC in Magicant. Also because Prime Rib is not an item like Omelets, there is no in-game description for this food.
- Because there is no Don't Care option in Mother, the player has to name Ninten's favorite food by themselves.
- It is impossible to name Ninten's food Prime Ribs in the English Prototype of Mother, due to English letters taking up more space than Katakana or Hiragana.
- Humorously, the MOTHER Encyclopedia, when mentioning prime rib, also states that "if there is another food [the reader would] rather eat, then that is [their] favorite," giving a nod to the in-game Favorite Food naming option.