You can try Kenzo Ramen on Yonge, south of Steeles. I've tried their takoyaki with octopus last time I went there with my boyfriend. The tasted was good and quite authentic, although not cheap. ($8 for 6 balls). I also liked their ramen.
There's a stand inside the food court of First Markham Place that caters to them as a specialty. First Markham Place is located at Hwy 7 & b/w Woodbine and Warden - same mall as Home Outfitters and Golf Town.