Pastas rhymes with:
anastas, augusta's, costas, kostas, maestas, mestas, preyistas, sabatista's, sabatistas, sabatistas', sandinistas, sandinistas', shasta's, vista's, vistas, zapatista's, zapatistas
Pastas sounds like:
packets, packwood's, pact's, pacts, pagoda's, pagodas, pas-de-deux, pastes, pastiche, pastiches, pasts, pectic, pesetas, pestka, pests, phagocytes, physicists, piaget's, pickets, pickett's, picts, pistachio, pistachios, pockets, posits, post's, post-attack, postage, postdates, posts, psychotic, pussycats