Pre-heat your oven to 400*F.
Add your dry ingredients to a bowl, including the coconut flour, almond flour, powdered monkfruit sweetener, baking powder, xanthan gum, cinnamon and salt. Whisk to combine.
Add your cold grated butter to the dry ingredients and gently stir to coat.
Add the sour cream, heavy cream, vinegar and whisked egg as well. Stir a few times, then also add in the blueberries.
Continue to mix gently, as to not crush the blueberries until you start to get a thicker crumbly mixture (use your hands to help mix everything).
Pour the crumbly mixture out onto a large parchment-lined baking sheet. Use your hands to push the dough together and form it into a large circular disc, about the thickness you'd like your scones. *If you find your dough too wet, add 1-2 extra tablespoons of coconut flour as needed. The dough should be crumbly and relatively dry, but should stick together when firmly pressed.
Slice the disc into 8 pieces and separate the pieces slightly on the tray to give them space to bake.
Brush the scones lightly with a bit of extra heavy cream.
Bake the scones for ~18-20min at 400*F, turn the heat down to 350*F if you continue baking past this time. Cover the scones part-way through baking with tinfoil to prevent them from browning too quickly on the top. If your oven heats more from the top-down, bake your scones on a lower rack. If it heats more from the bottom-up, bake them on the top rack.
Once the scones have cooled, whisk together the 3 ingredients for the glaze. Drizzle it over-top of each scone.
When the glaze has hardened, serve the scones with a side of coffee or tea. Enjoy your Keto Coconut Flour Blueberry Scones!