Preheat oven to 375 degrees F. Line a muffin tin with cupcake papers and grease with cooking spray.Using a rasp, zest the peel of one medium orange (avoiding the white pith). Next juice the orange and set both aside.In a medium bowl whisk together the flour, baking powder and salt.In a large mixing bowl beat the butter and sugar until light and creamy, approximately 2 minutes. Add the eggs one at a time, beating well after each addition. Add the vanilla extract and blend well again.Using a spoon, stir in the flour mixture just until blended.Add the orange juice, orange zest and milk and stir to combine. Then, gently fold in the cranberries.Using a two (2) ounce cookie scooper place the batter into the prepared muffin tin. Then, add the reserved cranberries to the tops wherever needed.Bake in a preheated 375 degrees F oven for 25-30 minutes, or until the tops are just a little firm but still soft to the touch.Let the muffins cool in the tin a few minutes before removing them to a cooling rack. Cool completely before glazing.For the glaze: In a small bowl blend together the confectioners sugar and orange juice until smooth and creamy. Using a spoon, drizzle the glaze over the muffins to cover the tops, a little may run down the sides, which is fine. Allow the glaze to set (harden) to a shiny finish.