How to Make It
Preheat oven to 350°. Melt 6 tablespoons butter in a 10-inch cast iron or heavy ovenproof skillet over medium heat. Tilt skillet to coat sides. Remove from heat, and stir in 1 cup brown sugar. Arrange pineapple on bottom of skillet; set aside.
Stir together flour and next 5 ingredients in a large bowl. Set aside.
Melt remaining 6 tablespoons butter in a small saucepan. Remove from heat, and stir in 1/2 cup hot water, molasses, and remaining 1/2 cup brown sugar. Whisk in egg.
Add butter mixture gradually to flour mixture, stirring until well blended. Pour batter into prepared skillet.
Bake 35 to 40 minutes or until a toothpick inserted in center comes out almost clean. Cool in pan 10 minutes. Invert cake onto a round platter. Scrape any sugar mixture left in skillet over cake. Serve warm or at room temperature.