Preheat oven to 350°. Beat butter at medium speed with an electric mixer until creamy; gradually add sugars, beating well. Add egg, beating until blended. Add molasses, beating until smooth.
Whisk together flour and next 8 ingredients in a large bowl. Add to butter mixture alternately with buttermilk, beginning and ending with flour mixture. Beat at low speed just until blended after each addition. Pour into 9 lightly greased (6-oz.) ramekins.
Bake at 350° for 24 to 28 minutes or until a wooden pick inserted in center comes out clean. Let cool on a wire rack 15 minutes. Serve warm with whipped cream, or drizzle with Rum Glaze.
Note: Gingerbread may be baked in a greased and floured 9-inch square pan. Increase bake time to 50 to 55 minutes.