Kossar's plaetzel is a flattened, irregularly shaped, roll, about 12" in diameter, with poppy seeds. There may or may not be onion sprinkled on it, usually not. Conceptually, it is related to the bialy, as it has a very yeasty dough. The one problem is that it must be eaten fairly quickly or it will go stale. A bialy, possibly due to being a little thicker, will last a few hours longer than the plaetzel. Sometimes, I use it similarly to a pita bread, carefully slicing it down the center and loading it with fun ingredients before or after toasting.
Both seem to freeze and recover well.
A little olive oil and herbs before popping into the oven. Pure heaven! I am drooling right now.