In a large bowl, combine the flour, sugar, baking soda and salt. In another bowl, combine the egg, buttermilk, orange juice, butter and orange zest; stir into dry ingredients just until moistened. Fold in cranberries and pecans.
Fill greased muffin cups three-fourths full. Bake at 375° for 18-20 minutes or until a toothpick inserted in the center comes out clean. Cool for 5 minutes before removing from pan to wire rack. Serve warm.