Why is unagi don hard to find at Japanese restaurants even though they got all the ingredients on the menu?
Well it is possible they do not have the right cooking apparatus . I believe the eel is roasted. Not fried or steamed. So they may not have the ability to cook it correctly. So they opt not to at all. But it is all possible that they just don't want to or do not want to cook it wrong. The cooks may not be versed in preparing Unagi Don. And would rather not make it in fear that they are not cooking it properly. But certainly asking is the first step. If they say no, not much you can do. Just reach out to the next restaurant and good luck!