If you need power then add power. If you need full power than use it.
Normally the first training stall will be without power to demo that it is not power that recovers you from the stall - HOWEVER-
The emphasis in stall recovery training is minimum height loss, there are also aircraft where full power can cause problem with pitch up - but even here the training on type should cover this, if you are stalling at height, then there may be times as an experienced pilot you might not want to use full power, but as far as most PPLs are concerned it
IS FULL power on recovery.