I'm expected to make this for some people on Sat, but I have yet to find a recipe that approximates the quality of what you get at a good Indian restaurant. I've tinkered with a bunch of variations on tomatoes, thinking this is the key (various combinations of whole/diced, pureed and paste). I've probably attempted this more than any other dish I've ever cooked! Most have been fine, but I haven't found the 'best'. Does anyone have a recipe they *absolutely* swear by? I'm only interested in a recipe for the sauce-- the marinated chicken always comes out fine.