Preheat the oven to 400°F. Lightly grease a standard muffin pan; or line it with papers, and grease the papers., In a medium-sized mixing bowl, whisk together the flour, baking powder, baking soda, salt, stollen spice, sugar, and the fruits and candied peel., In a separate bowl, whisk together the egg, buttermilk or yogurt, and melted butter., Quickly and gently combine the dry and wet ingredients; this should only take a few stirs with a bowl scraper or large spoon. The batter will be stiff., Spoon the batter into the prepared pan, filling the cups about 3/4 full., Bake the muffins for 20 minutes, until a cake tester or toothpick inserted into the center of one muffin comes out clean., Remove the pan from the oven, wait 5 minutes, then transfer the muffins to a rack., Brush the tops of the muffins with the melted butter, then dust with sugar., Serve warm or at room temperature., Yield: 12 muffins.