Adjust oven rack to lower-middle position and preheat oven to 400 F.
In a medium bowl, mix flour, sugar, baking powder, baking soda and salt. Cut chilled butter into dry ingredients. Use your fingers to work the butter in so that the mixture resembles coarse meal.
Stir in orange zest and dried cranberries.
In a small bowl, whisk egg and sour cream until smooth.
Using a fork, stir wet mixture into dry mixture until large dough clumps form. Use your hands to press the dough against the bowl into a ball. The process of pressing will make the dough gently come together.
Place dough on parchment paper and pat into a 7-8 inch circle about 3/4 inch thick. Sprinkle with remaining 1 Tbsp of sugar. Use a sharp knife to cut into 8 triangles; place on a cookie sheet lined with parchment paper about 1 inch apart. This will make cute triangle shaped scones.
Bake until golden brown, about 15-17 minutes. Cool 5 minutes on cookie sheet and then move to a rack to finish cooling or even better, serve warm!