Green’s Dictionary of Slang

onions (Cockney pron.).

1833		‘Knowing Bill’ in Rake’s Budget in Spedding & Watt (eds) Bawdy Songbooks (2011) III 86: Salt cod I sell a vind a pound, / Red herrings twelve a flag / I sometimes hinguns cries around, / A quart, sir, for a mag.
1837		‘Now!’ in Rum Ti Tum! in Spedding & Watt (eds) Bawdy Songbooks (2011) III 169: I’ll cry inguns round the street.
1879		G.R. Sims Dagonet Ballads 77: There ain’t no poetry in green-stuff — in ’taturs and inguns, and peas.