VARIANT FORMS:also hot cake
NOUN:See pancake. IDIOM:go (or sell) like hotcakes (Informal) To be disposed of quickly; be in great demand: 'Programs for the championship game went like hotcakes.' http://www.bartleby.com/61/6/H0290600.html
hotcake - PANCAKE
- like hotcakes : at a rapid rate <selling like hotcakes>http://www.m-w.com/dictionary/hotcake
sell like hot cakes - (informal) be sold quickly and in large quantities.
go or sell like hot cakes - to sell or disappear rapidly; to be extremely popular. <http://www.chambersharrap.co.uk/chambers/chre...
It does seem to be another AE/BE difference. Either 'go' (more common) or 'sell' is okay, but the standard form in AE is indeed 'hotcake,' one word, which correctly reflects the pronunciation, namely, with one accent on the first syllable, not two equal accents. Hotcakes are pancakes, which are so addictive that you can't eat just one, you keep coming back for seconds and the cook has to keep making more. 'Hot cakes' in AE would be, if anything, birthday cakes that had been kept in a hot oven.
Of course, 'hot cakes' did exist a few centuries ago when the expression was created, when vendors sold food on London streets and a cake was not a large dessert but a small snack. But at this point, I wouldn't even bother to include 'hot cakes' as an AE variant, since the two-word form is archaic IMO. (Well, NOAD doesn't seem to have noticed yet, but this wouldn't be the first error in it that betrayed its BE origins.)
As for the Google hits, for months or possibly a year or two now they have apparently had an algorithm in place that returns hits for spelling variants similar to the requested term, not just the exact spelling. That means that if you search for a past tense you may get present tense forms, plurals for singulars, adjectives for nouns, open compounds for closed, misspellings for correct spellings, and even totally unrelated words that happen to differ only by a letter or two (don't ask about, for example, searching for 'MIDI' in the sense of an audio music file and getting hits for 'mid'). 'Do no evil,' my foot. This supposed 'feature' drives me stark raving mad, and I have already complained about it more than once, to no avail. I can understand setting that as a default, but there ought to be an easy way for users to turn off that option, just like you can turn off spell-check in your word processor.
If it annoys you too, all I can suggest is to find the link at the bottom of your Google page that says 'Dissatisfied? Help us improve,' and send them a message every single time you get wrong results. I'm afraid it would take tens of thousands of us to get their attention, not just a couple of dozen, but who knows, it might have some effect -- so be sure and tell all your friends. (-: