Pavê is a typical Brazilian pie. It is composed by multiple layers of sweet crackers, cream and cake. Pavê is eaten often as a dessert in December holidays.
Because of the spelling of the word, there is a very famous double meaning joke related to the pavê in Brazil. "Para" means "to" in Portuguese. "Ver" means "see" in Portuguese. In spoken language, people say "pa" instead of "para" and people say "vê" instead of "ve...r". That's why "pavê" means "to see" in a literal translation to English. "Comer" means "eat" in Portuguese. So, the joke is: when the hostess say that there is "pavê" for "dessert", someone who is invited to the dinner asks if it is "pavê" or "pacomê". It means: he is asking if it is "to see" or "to eat". This is funny because it is odd that a kind of food is "to see" and not "to eat" according to its name. That's why this joke exists.
Not everyone makes this joke. There is a stereotype of people who make this joke: it is usually men aged between 40 and 70. Young people consider this joke old and boring.