Probably the simplest solution to this is to record the voice with the mic slightly further away. The clicks and pops you are hearing are vocal and throat artifacts which are only getting picked up because you have the mic so close. Also try and position the mic slightly off-axis - this will also help smooth the sound.
I can't hear the metallic quality you mentioned but I can hear an amount of 'vocal fry'.
My feeling is that this is more about your performer than the recording technique.
Talk to them about their warm-up routine and make sure they have water available and keep sipping during the session.
If there is a particular behaviour that's causing a problem (such as ...