Preheat oven to 400 degrees F. Grease twelve to fourteen 2 1/2-inch muffin cups or line with paper bake cups. In a medium mixing bowl, toss cranberries with 2 tablespoons sugar; set aside.
In a large bowl, combine flour, 1/3 to 1/2 cup sugar, the baking powder, orange peel, and salt; stir well. In a small bowl, combine egg, buttermilk, and butter. Make a well in center of flour mixture; add egg mixture and cranberries. Stir just until moistened (batter should be lumpy). Spoon into prepared muffin cups. Sprinkle tops with coarse sugar.
Bake muffins about 15 minutes or until golden and a toothpick inserted comes out clean. Cool on a wire rack. Serve warm.