vantage loaf, n. — Green’s Dictionary of Slang

vantage loaf n.

[SE vantage, an advantage, in this case to the buyer; note synon. 17C SE vantage of bread]

the 13th loaf in a ‘baker’s dozen’.

1890–1904		Farmer & Henley Sl. and Its Analogues.
1893		Newcastle Courant 25 Nov. 2/1: The thirteenth loaf given to the dozen was called the ‘vantage loaf’.
1943		Eve. Teleg. (Dundee) 17 Mar. 2/3: The thirteenth of a dozen was the ‘vantage’ loaf.