Butter boat

a small vessel for holding melted butter at table.

See also: Butter

References in classic literature ?
Very clever were some of their productions, pasteboard guitars, antique lamps made of old-fashioned butter boats covered with silver paper, gorgeous robes of old cotton, glittering with tin spangles from a pickle factory, and armor covered with the same useful diamond shaped bits left inn sheets when the lids of preserve pots were cut out.
Then there were the butter boats and the potato boats.