The invention relates to a method of preparing cannabis extracts, including shatter, budder and wax extracts. The extraction method can provide a high quality and pure extraction product of THC from cannabis plant material, as either a shatter, wax or budder end extraction product. The extracted product is free of polar cannabis plant material, chlorophyll and residual solvents, has a high concentrate of THC, and can be used for dabbing, vaping or smoking consumption by a user. Suitable solvents for the method are gases selected from the group consisting of propane, butane or iso-butane, and the preferred solvent is propane. A key step of the method of the present invention is recovering solvent under atmospheric vacuum and, therefore, obtaining an extraction product that is purified of solvent and has no solvent.