I stumbled into Don Quijote by accident. I had just gone for a long run in nearby Osaka Castle, then showered at a runner's facility, and as is typical for me during my year in Japan, was searching for a place at which to overeat.
Located on the second floor of a nondescript building on a commercial street with a bunch of different restaurants, Don Quijote definitely doesn't stand out. But for the photograph outside of a large Frankenstein-looking okonomiyaki, I never would have given it a second look. But I'm glad I did.
The house signature okonomiyaki features octopus, shrimp, squid, chicken, pork and an egg on top of a traditional Osakan savory pancake. It is beyond epic. Please be aware that you can only order it for dinner though, as the restaurant serves strictly set meals at lunch. The chef/owner loves classic rock music so there's always a good soundtrack here. Make sure you ask him about his love for the band Kiss!!
ALSO RECOMMENDED: Eggplant (なずび).