Earlier quoted context omitted.
It used to be iced cream, which is more descriptive. Ice cream is a shortened pronunciation.
When was called it "iced cream"? The first published recipe for ice cream in 1718 called it "ice cream", not "iced cream". The first recorded mention in English at all was in 1671 and there, again, it was "ice cream", not "iced cream".
There are some attestations to it from 1732 onwards: https://archive.org/search?tab=fulltext&query=%22iced+cream%...
The attestations for ice cream (or often ice-cream, as these open compound words used to often be hyphenated -- the loss of that hyphen eventually leading to articles like this one) are much, much more and much messier, not least because someone tagged every edition of The Gentleman's Magazine as being published in 1731 -- the Internet Archive is a fantastic resource but I wish they'd allow crowd sourcing corrections for metadata. Excuse the m-dashes.
You may be right that it was mostly called ice cream at first and eventually at last. To be honest I took the Wiktionary etymology at its word.