Freeze 1/2 stick of butter. Using a food processor or box grater, grate the butter. Place grated butter in a freezer bag and return to the freezer until just before needed.
Preheat oven to 400º
Combine the flour, baking soda, salt, and sugar in a large mixing bowl. Briefly blend in the frozen butter using an electric mixer set at the lowest speed and fitted with the paddle.
Combine the egg and heavy cream in a separate bowl and beat lightly. Add the cold ingredients to the butter and flour mixture and blend until combined.
Remove the dough to a well-floured surface. Flour your hands and shape the dough into an 8″ disc. Then cover with plastic wrap and refrigerate for at least an hour or overnight.
With a sharp knife or pastry cutter, cut the dough into quarters. Then cut each quarter in half to make 8 scones.
Place the triangles on a prepared baking sheet lined with parchment paper and brush the tops with heavy cream. Sprinkle with Turbinado sugar, pop them in the oven, and bake 20 to 25 minutes until golden brown.
Remove the scones from the oven and place them on a wire rack to cool.
Once cooled slightly, drizzle a little glaze, if using, over the top of each scone. Enjoy!
Notes
For the icing, mix a little lemon juice with powdered sugar and whisk until you get the consistency you want.