Servings: 12

10 tablespoons unsalted butter, frozen 10 tablespoons unsalted butter, frozen
7 1/2 ounces blueberries or more! (approx. 1 ½ c.) 7 ½ ounces blueberries or more! (approx. 1 ½ c.)
1/2 cup whole milk, cold ½ cup whole milk, cold
1/2 cup sour cream, cold (original recipe called for 1/3 cup) ½ cup sour cream, cold (original recipe called for ⅓ cup)
10 ounces unbleached, all-purpose flour (approx. 2 c.; plus more for work surface) 10 ounces unbleached, all-purpose flour (approx. 2 c.; plus more for work surface)
3 1/2 ounces granulated sugar (approx. ½ c.) 3 ½ ounces granulated sugar (approx. ½ c.)
2 teaspoons baking powder 2 teaspoons baking powder
1/4 teaspoon baking soda ¼ teaspoon baking soda
1 teaspoon grated lemon zest 1 teaspoon grated lemon zest
1 teaspoon kosher salt 1 teaspoon kosher salt
4 T. King Arthur Sparkling White Sugar for finishing 4 T. King Arthur Sparkling White Sugar for finishing

Adjust oven rack to middle position and heat oven to 425 ℉. Prepare a baking sheet with parchment or a silicon matt.
Whisk the flour, ½ c./3 ½ oz. of the sugar, baking powder, baking soda, salt and zest in a medium bowl. Grate 8 tablespoons of butter directly into the flour, stirring it up occasionally to cover the bits of butter with flour.
Whisk together the milk and sour cream in a separate bowl. I find it easier to measure the sour cream by first adding the milk to a measuring cup and then add enough sour cream to bring the whole thing to 1 cup.
Melt the remaining 2 T. of butter and set aside for later.
Add the chilled milk mixture to the dry ingredients and fold with clean hands until just combined.
Transfer the dough to a liberally floured work surface. Lightly dust the dough with flour and with floured hands, knead until it just holds together in a ragged ball, adding flour as needed to prevent sticking. With a floured rolling pin (or a handy wine bottle), roll the dough into an approximate 15" by 10" rectangle.
You may want to chill the dough in the refrigerator for 15 minutes if you moved a bit slowly through the previous step to make sure the butter is still firm.
Sprinkle the blueberries evenly over the surface of dough, then press down lightly to just merely embed them into the dough, leaving the top 1" free of berries.
Using a bench scraper, lift one end of the dough, beginning to roll into a tight log. Lay, seam-side down, and press the log into a 15" by 4" rectangle. Using a sharp, floured knife (or even the bench scraper you've been using), cut the rectangle lengthwise into 6 equal portions. Cut each square in half diagonally to end up with 12 triangles, transferring each to a parchment-lined sheet pan.
Brush each triangle top with the reserved melted butter and sprinkle evenly with the sprinkling sugar.
Bake until tops and bottoms are golden brown, 18 to 25 minutes, rotating the pan halfway through.
Transfer to a wire rack and allow to cool for at least 10 minutes before serving.

Note: After shaping and cutting, the scones can be frozen and transferred to a ziplock freezer bag for long term storage. Bake from frozen, adding 3 - 5 minutes onto the total baking time.  Note: After shaping and cutting, the scones can be frozen and transferred to a ziplock freezer bag for long term storage. Bake from frozen, adding 3 to 5 minutes onto the total baking time.