How do you say peanut butter in Spanish?
It really depends on the country. In Mexico it is "crema de cacahuate" (for smooth) and "crema de cacahuate con trozos (for chunky).
I have also seen references to "mantequilla de cacahuete" (notice the difference in spelling for the word "peanut") and "crema / mantequilla de maní".
En argentina, uruguay y chile se dice "manteca de mani" ya que peanut es mani y butter manteca. No utilizamos la palabra matequilla Good luck!
It does indeed depend on where you are. When I shopped for peanut butter in Costa Rica, it was only "mantequilla de mani" that succeeded in getting me the desired results.
Cacahuate / cacahuete is from the Náhuatl word cacáhuatl, which is used probably only in Mexico, so mani will be understood in any other country where Spanish is spoken. We learn a lot of words there from childhood that come from Náhuatl, ie: mecate from mecatl means cuerda in Spanish and we also use this particular word in an idiom A todo mecate meaning A todo dar / Muy bien.