Green’s Dictionary of Slang

crug n.

food.

1823		(con. late 18C) C. Lamb Essays of Elia 28: He had his tea and hot rolls in a morning, while we were battening upon our quarter of a penny loaf— our crug— moistened with attenuated small beer.
1853		Dickens ‘Slang’ in Household Words 24 Sept. 76/1: Food is grub, prog, and crug.
1860		Hotten Dict. of Modern Sl. etc. (2nd edn).
1935		A.J. Pollock Und. Speaks 27/2: Crug, rice-bread.
1940		M. Marples Public School Slang 54: crug (Christ’s Hospital) bread, at Hertford crust only. [...] Charles Lamb used it in one of his essays on Christ’s Hospital of the ‘quarter of a penny loaf’ which formed a boy’s breakfast in his time.