Dream-come-true Coffee Cake

Heat the oven to 375 degrees. Grease a 9-inch cake pan with 2-inch sides. In a large mixing bowl, combine all the dry ingredients. In a medium-size bowl, combine the butter, egg, and buttermilk. Add the buttermilk mixture to the dry ingredients and stir until combined. Pour the batter into the prepared pan. Mix together all the topping ingredients and sprinkle evenly over the batter. Run a knife or spoon through the pan, allowing the topping to invade the batter. You don't want to mix the two; you're aiming for a marbled effect. Bake for 25 to 30 minutes or until a toothpick comes out clean. Serve warm. Serves 8.