In a large bowl, combine the flour, sugar, baking powder and salt. In another bowl, whisk the eggs, buttermilk and butter. Stir into dry ingredients just until moistened. Fold in cranberries and chocolate.
Fill greased or paper-lined muffin cups two-thirds full. Bake at 400° for 15-18 minutes or until a toothpick inserted in the center comes out clean. Cool for 5 minutes before removing from pans to wire racks to cool completely.
In a small bowl, combine the confectioners' sugar and enough cranberry juice to achieve drizzling consistency. Drizzle over muffins.