This takes the "SFBI" steam method to the next level.
There are two changes to the standard SFBI method: first is the use of a half inch round steel plate instead of lava rocks or bolts. This allows the second change: heat the steel plate and the skillet on the stovetop to whatever temp you want. I took the temp up to 550° with great results. The steel plate weighs 5.75 pounds and holds an incredible amount of heat.
The advantages are that the round steel plate has far more thermal mass than lava rocks or nuts and bolts, you can bring the whole thing to a much hotter temperature by heating directly on the stovetop, and by heating the steel to higher temperature you have less heat loss in the oven. The plates heat quickly on the stove, so my guess is that it is more energy efficient also.
You can have a local metal shop cut the round plate for fairly minimal cost, or probably order one from BakingSteel Co. The skillet is standard 9" Lodge cast iron. The perforated pie plate is made by Chicago Metallic and is available on Amazon.
An infrared thermometer is recommended to get a temperature reading of the steel on the stovetop.
BE EXTREMELY CAREFUL WITH THIS STUFF! USE HIGH QUALITY MITTS!
DONT PLACE ICE ON SKILLET UNTIL AFTER THE HOT SKILLET IS PLACED IN THE OVEN!
DON'T USE THIS TECHNIQUE IF YOU AREN'T CAPABLE OF BEING SAFE!