Preheat the oven to 375°F.
In a 10-inch cast-iron skillet, melt the butter. Add the brown sugar and stir until the sugar is melted and mixed with the butter.
Drain the pineapple and arrange mixture in the skillet. Pour the sugar mixture in the center of each pineapple slice. Place pecans evenly over the top. Set aside.
In a large bowl, beat the egg whites until stiff peaks form. Add the sugar gradually until completely beaten and combined.
In another bowl, combine the flour, baking powder and salt. Add the mixture and bourbon and beat until combined.
In a small bowl, beat the egg whites with an electric mixer on high speed until stiff peaks form. Fold the egg whites into the batter. Pour the batter into the skillet, making sure all the pineapple pieces are covered well.
Bake for 30 to 35 minutes, or until a toothpick inserted in the center comes out clean. Let stand for a few minutes before turning upside down onto a serving plate.
Serve warm.