I forgot to mention, I used half an onion for the bone broth. Also for the purist critical mind side of yours, nostrichmen, the name molcajete is given to the stone that is used to crush the ingredients; the base stone is usually called mortero; although probably there's a more ancient name for it.

As for the final grind; add some of the bone broth, no more than a cup will suffice but you could go crazy. Also this is the right time to add fresh ingredients to the mix, I put onion, garlic and cilantro leaves. You can put a little more salt, though not much!