So how do we burn the miraculous image onto the tortilla?   With a heat gun, of course.  I use the Steinel HL 1502 S.  This thing requires a standard 120 volts AC, and produces up to 1,050° F.  It's generally used for removing paint, but I use it for caramelizing browning sauce on tortillas. 

Now, I understand that this is not the sort of thing that everyone has lying around the house.  I only acquired one for a ill-concieved body modification business I was starting.  But it's perfect to get the seasoning sauce to burn properly.  Just frying your tortilla in a pan doesn't offer enough control.  And a hair dryer won't get hot enough.  The Steinel costs about $80, although you can get other brands for less.

I have thought about using a creme brulee torch instead, but I have not purchased one yet.  If anyone tries it, let me know how it goes.  A creme brulee torch would cost about $20.