Lox and cream cheese on cinnamon toast?!

I use this line from time to time when I am at a place that does kitchen call outs like that. My girlfriend gets it, but waiting for the day when some stranger does.

I don't get this joke. How would John Candy within his dream world know that this woman liked this type of food? Was there a scene cut out that explained this? I saw it edited for TV and there were some weird edits.