1. Preheat the oven to 375 degrees F. Coat a baking sheet with cooking spray and set aside.
2. Combine the flour, 3 tablespoons of the sugar, baking soda, salt and butter-flavored spread in a food processor and pulse until spread is uniformly incorporated into the dry ingredients. Transfer the mixture to a large bowl and set aside.
3. Combine the buttermilk, egg and vanilla in a small bowl and whisk to mix well. Stir in the orange zest. Add the buttermilk mixture to the flour mixture and stir just until moistened.
4. Transfer the dough to a lightly floured surface, sprinkle lightly with flour, and using floured hands, shape the dough into a 9-inch square. Cut the dough into 9 squares and transfer to the prepared pan, spacing about 1/2 inch apart. Sprinkle evenly with the remaining 1 tablespoon of sugar. Bake 12 to 14 minutes, or until the tops of the scones are lightly browned. Serve immediately.