Green’s Dictionary of Slang

1. (US black) anything outstanding, wonderful or first-rate [the presumed excellence of home cookery].

1938		Eve. Sun (Baltimore, MD) 19 Dec. 21/4: Home cooking: very fine.
1944		Cab Calloway New Hepsters Dict. in Calloway (1976) 256: home-cooking (n.): something very nice.
1944		‘Jiver’s Bible’ in D. Burley Orig. Hbk of Harlem Jive.
1965		(con. 1930s) R. Wright Lawd Today 107: ‘Now, ain’t that something!’ ‘The hottest stuff in town!’ ‘This is homecooking!’.

2. (US) sexual intercourse, usu. from a man’s point of view with his wife.

1966

Trimble 5000 Adult Sex Words and Phrases 100: home cooking (Sl.) Sexual intercourse, usually Copulation with one’s wife.