Preheat the oven to 250 F and break up the pieces of chocolate (or, in my case I just used little medallions).  Line a baking sheet with a silicone mat (like these ones) and spread your white chocolate pieces across the pan.  Put it in the oven for 10 minutes. 

After 10 minutes it will have softened and begun to melt.  Then use an offset spatula (I prefer a small one) to smooth out the now-melted chocolate.  It should be nice and melty, though will have some bumps.

Return it to the oven for 15 minutes (total time in oven so far = 25).  It should be really taking on some color, especially once you scrape the bottom and flip it over.  Keep stirring it to get the bottom all flipped over and then stir everything together.  Bubbles and bumps are still totally normal.

Put it back in for another 10 minutes (we're at 35-ish minutes now).  Every time you take it out of the oven, repeat the process of scraping the bottom and turning it over, to avoid things burning or browning unevenly.  Stir it together and smooth it out.

At this point it could be done, but I put it in for another 5-10 minutes to really deepen the color.  

If you have a food processor, scrape the melted chocolate into the bowl and process until really creamy.  The original recipe says 5 minutes, but this took less than 30 seconds in my food processor.

Otherwise you can use your spatula to smooth it out, really putting some elbow grease into the stirring to get rid of the remaining bumps.

Line a pan with parchment paper (mine was a 9x9 pan) and pour your melted caramelized white chocolate in there.  I might do a 9x13 next time to have thinner chocolate that's easier to cut into pieces...however fitting that in my fridge is difficult.  Put it in the fridge to fully solidify, then break up using a large knife.