1.Preheat oven to 400 and line a large baking sheet with parchment paper.
2.Mix granulated sugar and lemon zest together until combined.
3.In the bowl of a standing mixer (or a large bowl if you don't have a standing mixer), mix flour, baking powder, and salt together. Next, add in the lemon sugar.
3.With a pastry cutter, a fork, or your standing mixer, work the cold butter (a few pieces at a time) into the flour mixture, until the mixture resembles coarse crumbs.
4.Mix heavy whipping cream and egg together, and slowly drizzle into the scone batter while stirring gently. Stir just until combined.
5.Lastly, add in the blueberries and fold in gently. (Some of the blueberries might open up as they're mixed; that is fine.)
7.On a floured surface, turn out the dough and pat into a 1-inch thick circle. Cut the dough into eight equal triangles.
8.Carefully place each scone on your baking sheet and brush with additional heavy cream (just a little bit--it gives the scones a nice golden color).
9.Bake for 18-20 minutes, or until scones are golden brown on top.
10.While the scones are cooling, mix together lemon juice, powdered sugar, and zest. Once combined, drizzle the glaze over the scones.
11.Allow the glaze to set before serving. Enjoy!