@JeremyCherfas Saltines are kinda like matzo cut into 2.54-cm squares and salted. I think they might be slightly leavened, but they are very dry.
Oyster crackers I think are made by pressing two layers together and cutting. They puff up and are hollow in the middle. They’re often less dry than saltines, so maybe a touch of butter/oil?
/@indigo @kdfrawg