Take some shredded cabbage and stir fry it in oil, along with a fair amount of bread crumbs, such as the Panko kind, and add some spices like salt, pepper, and garlic, along with a little sweet vinegar if you like.
Toss it into a big bowl, pour some soy sauce over it, and maybe have dipping sauce on the side, like dijon or hot mustard. Ah so! Well, I wasn't setting out to make anything in particular with that, but since it tastes about the same, I might as well call this a bowl of egg roll... (cue gong sound effect).
Egg rolls do not typically contain egg in the filling, and the wheat flour wrapper may or may not contain egg. In addition to the disputed origin of the dish, it is unclear how the word "egg" appeared in the name, since the predominant flavor in American egg rolls is cabbage, not eggs.
My guess would be eggplant, or at least there are several recipes with that and cabbage together, so of course it could go in an egg roll (as if it were named after this). I've since noticed that there are other recipes out there for an "egg roll in a bowl". They don't seem to use bread crumbs though. Those are good for soaking up extra oil in a stir fry, so they'll clean the pan for me, and can also be used in salads like croutons. Funny, these also reminded me of fish and chips, when mixed into a bowl of cold cabbage with oil and vinegar. I guess the longer I go without eating those kinds of things, the more my imagination fills in the blanks. Besides, who makes any of it without the seasonings? That's what recipes are all about.