Preheat your oven to 375 degrees. In a cast iron skillet or a 9 inch cake pan, melt the butter for the topping over low heat. Stir in brown sugar until it has dissolved and turn off the heat but leave the pan on the eye.
Meanwhile, cream the butter and sugar (for the cake) together with a hand mixer of stand mixer. Add the eggs in one at a time along with the vanilla. Mix the flour, baking powder, salt and other seasonings together in a small bowl and then add to the batter on LOW speed until mixed together well.
Arrange the pears in the sugar mixture in the bottom of your pan and then dollop the batter on top of the pears. Spread the batter into an even layer and then bake for 30-40 minutes or until a toothpick comes out clean.
You need to remove this cake from the pan pretty quickly or you will have a mess on your hands. Once you remove from the oven and the edges stop bubbling, place your cake plate on top of the pan and in one movement while holding the plate and the pan together tightly, flip the pan and cake over onto your serving platter. Voila!