What you do is you built the fire:

You light the fire, but before the progress bar is done, you right click for the "light my Fire" and wait until the fire is lit. All you have to do is light it again:


This way you get twice the LP from doing the same action twice:

ALSO, this doesnt seem like much, but with the other discovered bug viewtopic.php?f=4&t=16407 you could have an entire house of fires that you could continuously relight times 2. Like an entire mansion, on both floors, or a third with a basement.