Luftwaffle's technique is by far the safest - read the NTSB Accident reports.
Brief for 'landing' with approach configuration and a simulated field at 4000'agl. You can even line up on a geographic feature for the 'runway' to make the student's life easier. Practice a low and over then, when clean and climbing, use throttle to simulate failure. Set zero thrust when student indicates feathering.
If I'd tried the mixture technique on a real climb out I wouldn't be posting today.
In Canada there is a requirement for a shutdown and air start for the rating. This is done within easy range of the runway at or above 3000'agl.
------------------
-.-- --.- -..-
edited for appalling typing
[This message has been edited by Code Blue (edited 04 February 2001).]