induction range What use is a cast iron frying pan full of rocks? By Dick Stein • Nov 9, 2011 Dick Stein / KPLU Hint: It has to do with baking. But first take a look at picture #2 above. I've had that picture for years and still have no idea what the thing is or does. If you do please share. And now the answer to the question posed in today's headline.