Plum Buckle Recipe

Preheat the oven to 350°F. Lightly butter a 9-inch cast-iron skillet. In a medium bowl, sift together flour and baking soda and set it aside. In an electric mixer, cream the brown sugar and butter until light and fluffy. Beat in the buttermilk, egg, and vanilla until smooth. Scrape down the sides. Add the flour mixture to the bowl while the beater is running. Scrape down and mix briefly, just until combined. Pour the batter into the skillet. Smooth it out—it will be very thick. Pour the plums over the batter and lightly press them down so they are partially submerged in the batter. Mix together the cinnamon and sugar and scatter it over the top. Bake the buckle on a lipped baking sheet for 40 to 45 minutes, until a toothpick inserted in the center reveals a moist crumb with no liquid remaining. Serve warm. Store loosely covered at room temperature for up to 3 days.