NOTE: We have adapted this recipe for a cast-iron skillet.
Line a 10-inch cast-iron skillet with aluminum foil, completely covering the bottom and sides and extending extra foil over edges of the pan. Preheat oven to 350 degrees F.
Make the topping: Place butter in skillet, place skillet in oven, and melt butter. As soon as butter is melted, remove and stir in brown sugar, carefully mixing well with a rubber spatula so as not to tear foil. Arrange pineapple slices over butter/sugar spread. Place cherries in center of pineapple and pecans between the slices.
Make the batter: In the bowl of an electric mixer, cream butter, adding sugar gradually, and then add eggs and beat well. Stir flour, baking powder, and salt together in a small bowl. Combine buttermilk, syrup, and vanilla in a small measuring cup. Add flour mixture alternately with buttermilk/syrup mixture, beating well after each addition. Spread batter evenly across mixture in skillet.
Bake for approximately 45-50 minutes, or until toothpick inserted in center of cake comes out clean. Place a large cake plate over pan, and invert to remove. Peel off aluminum foil, pressing back any pineapple that may be stuck to the foil.
Recipe from The Unofficial Mad Men Cookbook: Inside the Kitchens, Bars, and Restaurants of Mad Men by Judy Gelman and Peter Zheutlin (Smart Pop, 2011).