Green’s Dictionary of Slang

pastry v.

[play on SE roll/roll v. (2a)]

(UK black) to roll a cannabis cigarette.

1999		(con. 1979–80) A. Wheatle Brixton Rock (2004) 21: Brenton pastried his joint.
2001		(con. 1981) A. Wheatle East of Acre Lane 78: Biscuit pastried his spliff and lit it.