1. Preheat oven to 400 degrees.
2. In a large bowl, mix flour, sugar, baking soda, salt and orange zest. Set aside.
3. Place a 1/2 cup of heavy cream into the freezer for 5-10 minutes. In the meantime, melt the butter, and squeeze the orange, straining out any seeds.
4. Add the butter to the chilled cream, along with the orange juice and vanilla extract.
5. Pour the cream mixture into the flour mixture, and stir until you have a crumbly dough. With your hands, bring the dough together, kneading a few times on a very lightly floured surface until mostly smooth.
6. Pat the dough into a rectangle, and cut out scones. Reshape dough as needed and cut. Place the scones on a parchment or Silpat lined baking sheet.
7. Brush the tops of the scones with heavy cream.
8. Bake the scones for about 12-14 minutes, or until the tops and bottoms are slightly golden.
9. Allow the scones to mostly cool, and then top with orange icing.

For the Icing

1. Add powdered sugar and orange zest to a small bowl. Start with 2 tablespoons of orange juice, whisking until you have a thick paste. Slowly add a tiny bit more juice until the icing is thick, but will just barely drizzle off the whisk.