Preheat the oven to 400°
In a mixing bowl, sift flour, sugar, baking soda and salt. Mix in orange zest
Add in cold grated butter and mix gently with hands or a wooden spoon. Alternatively, you can cube the butter and cut it into the dough with a pastry cutter or two forks until pea sized balls form.
Pour in heavy cream and egg and gently mix until all flour has been moistened, but it does not yet form a solid ball
Pour the loose dough on a floured surface. Form the dough a disk, about 1 inch thick. Cut the disk into 8 triangles.
Place the scones on a baking sheet lined with parchment. Brush the tops with some additional cream and bake in the oven for 14-15 minutes or until slightly golden brown. Place on a cooling rack and allow them to cool completely.
While the scones are cooling, mix together all glaze ingredients. Spoon or pour the glaze over the tops of the scones and wait a few minutes for the glaze to solidify. Enjoy.