Haven't found a place that does American pancakes in Sheffield. If there was such a place they'd be loaded (hopefully).
I think someone's mentioned to me that Damon's in Beighton (Crystal Peaks) does an American breakfast, but I must admit I've never eaten there.

Bear in mind when you see pancakes on a menu 9.9 times out of 10 they're referring to Crepes.
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On another note, there is however a burger joint on Ecclesal Road (near Waitrose) called Yankees that's supposed to do good American style burgers. I've just never gotten around to trying it, but its been recommended to me by a friend in Chesterfield.