I just remembered that the original recipe I adapted that pate technique from included an anchovy or two, probably to kick the salt/flavor up a notch. That is tasty but not required; you can use all sorts of things to produce a more intensely flavored result: lemon juice, bacon salt, hot sauce, cumin, garlic and/or onion powder, sumac … whatever you like.
BTW, the reason I stopped consulting the original recipe was that it used meat and butter in equal amounts. That was far too much for me - if I want butter on a cracker, I’ll just put butter on a cracker and skip the other steps. But if you feel like adding more butter, the originator of the recipe would agree with you.