marsh-mallow paste(1857)

[Sam Clements]

OED has 1883 for 'marshmallow' as a confection.  

17 Jan. 1857  _Ft. Wayne(IN) Sentinel_   4/4

An advertisement using NewspaperArchive

<<Marsh-Mallow Paste--Jujube Paste--Lemon, Rose, Banana, Pine-Apple-Liquorice.  Hourhound(sic), Wild-Cherry and Iceland Moss Gum Drops for ???(obscured)  
-------Apothecaries Hall>>

I realize that this isn't what we know as the marshmallow today.  I think, from reading an 1880 cite that they made 'drops' out of it before the modern marshmallow.

Sam Clements