Green’s Dictionary of Slang

(drugs) manufacturing illicit drugs, e.g. heroin or crack cocaine; also cooking house, a place where these drugs are prepared for consumption; cooking spoon, used to prepare the drug.

1985		(con. 1968) D.A. Dye Citadel (1989) 304: Doctor eyed the pile of plastic bags, cooking spoons and spikes.
1990		S. Morgan Homeboy 32: The water vial, syringes, cotton balls, and cooking spoon.
1992		T. Williams Crackhouse 147: cooking – practice of heating cocaine to produce a hardened mass of freebase.
1995		(con. 1985–90) P. Bourjois In Search of Respect 78: He ran every detail of his crackhouse operation with the exception of the ‘cooking’ of the crack — its processing.
1997		L. Davies Candy 195: The cooking became a meticulous routine: breaking open the capsules (‘shelling the peas’), mixing the powder with water, extracting the codeine with a vacuum aspirator and throwing out the paracetomol, separating the codeine from the water with dichloromethane, then evaporating the dichloromethane and dissolving the pure codeine in a re-agent, the heating of which resulted in a morphine freebase.