Line a baking sheet with parchment paper. Set aside.
In a mixing bowl, whisk together an egg, buttermilk, vanilla extract, and lemon extract. Set aside.
In a separate bowl, mix together granulated sugar and lemon zest. Add the remaining dry ingredients - all-purpose flour, baking powder, baking soda, salt, and cinnamon. Then, add cubed cold butter and combine using a pastry blender or your hands until the mixture resembles coarse crumbs.
Gently add the wet ingredients and the blueberries to the butter mixture and mix with a rubber spatula until just combined. Don’t overmix. Flour your hands (the dough will be sticky) and transfer the dough to the lightly floured surface. The dough will be slightly sticky. Knead the dough slightly and form an 8-inch circle. Cut into 8 wedges using a sharp knife or a bench scraper.
Place the scones on the prepared baking sheet, leaving about 2 inches between each scone. Brush with heavy cream and sprinkle with coarse sugar. Refrigerate for about 20 minutes.
Preheat the oven to 400°F. Bake the scones for 20-25 minutes or until golden on top and the edges are golden brown. Remove from the oven and let cool completely.
While the scones are cooling, prepare the lemon glaze. In a small bowl, whisk together confectioners sugar, lemon juice, and melted butter until smooth. Drizzle the lemon glaze over the cooled scones. Enjoy!