What does one usual eat with this potato dish....meat....fish...
A pastrami sandwich...what else?
Okay, corned beef if you must, of coupla dogs with brown mustard and saurerkraut (preferably natural casing) or maybe a "special" or two.
I like knishes as a side with steak.
I've had them in the morning with eggs.
I would eat them with fish.
As noted above, although i don't always, I've eaten knish with mustard. S'alright.