Line two baking sheets with parchment paper and/or Silpat Mats.
In a large mixing bowl whisk together the flour, granulated sugar, salt, baking powder, and baking soda. Add 2 ounces of cold cream cheese and the butter, both cut into small pieces. Using your fingers or a pastry cutter, incorporate the butter and cream cheese until the mixture resembles a coarse meal. Put the flour mixture in the freezer for 30 minutes.
Preheat the oven to 425 degrees placing the racks in the upper and lower thirds of the oven.
Remove the flour mixture from the freezer and fold in the blueberries. Gradually add the buttermilk, folding the mixture carefully as so not to break the blueberries. The dough should be sticky and lumpy.
Divide the dough into 8 even sized mounds on the two baking sheets (4 on each sheet spaced 2 inches apart). Sprinkle each with about 1 teaspoon turbinado sugar.
Bake, rotating the sheets halfway through, for about 20 minutes or until the shortcakes are lightly browned. Let the shortcakes cool on the pan for at least 5 minutes then transfer to a wire rack to cool completely.
When ready to serve, beat together the remaining 6 ounces of cream cheese with the confectioners’ sugar with a mixer until smooth. Gradually add the cream beating just until it becomes thick and and smooth. Do not over-beat.
Serve with shortcakes and blueberries and sprinkle with confectioners’ sugar if desired.