If I don't have a cast iron skillet, what can I use?
This question references CHOW's Skillet Pear Cake recipe.
Any oven-safe skillet will do. If you don't have one, then use an 8" round cake pan or springform (wrap the base of the springform in foil, to catch any butter leaks). Just make the brown sugar mixture in a small sauce pan, then pour into your cake pan. Proceed with the rest of the recipe.
Make the caramel in a sauce pan, and assemble sauce, fruit, and batter in a cake (or Pyrex or baking) pan comparable in size to the cast iron. Keep an eye on it; my guess is that it might go more quickly although 30 - 35 mins seems like a reasonable amount of time either way. No sweat!