A Pot Noodle is a form of dehydrated food, presumably based on the real world product of the same name. As mentioned a few times, Pot Noodles are Dave Lister's least favourite food, as opposed to his favourite curry, although he has never stated precisely why he dislikes Pot Noodles so much.
Lister demonstrated his hatred for Pot Noodles when, food supplies running low, he preferred to eat dog food. ("RD: Marooned")
Lister has also suggested that he would be impressed by any technology that could take a Pot Noodle and turn it into food. In the High version of Red Dwarf he encountered what he thought to be impossible, an edible Pot noodle. ("RD: Demons & Angels").
Despite his hatred for Pot Noodles, Lister chose to cook with one in "Can't Smeg, Won't Smeg".