I know this, because I just made some. From scratch. By accident.
Minus the green onions, the batch I made is the exact same thing, down to the crispy crust and the chewy texture. Even without soy sauce and rice vinegar to dip, the taste is unmistakable. Worse, it's the best 蔥油餠 (minus 蔥) I've ever had--better than the stuff my favorite street stands have been making for decades. Maybe it's because it's freshly made?
It's delicious, but I feel slightly cheated. (No wonder they sell it for so cheap...)
(update) Wait. This is indeed the same stuff I've had at roadside stands, but I just remembered there is a better variety, only served in nice restaurants. There's a layered texture to theirs, and it's uniformly crisp, and the center is soft but not doughy, and is full of little air pockets for trapping sauce. Perhaps there is some technique to this dish that I have not yet mastered. That makes me feel a little better.