From: America's Test Kitchen (modified to make it less fussy)
Makes 8 - deliciously light.
It is important to work the dough as little as possible—work quickly and knead and fold the dough only the number of times called for. The butter should be frozen solid before grating.
Refrigerate or freeze leftover scones, wrapped in foil, in an airtight container. To serve, remove foil and place scones on a baking sheet in a 375-degree oven. Heat until warmed through and re-crisped, 8 to 10 minutes if refrigerated, 16 to 20 minutes if frozen. See final step for information on making the scone dough in advance.
INGREDIENTS
4 oz frozen butter (1 stick)
8 oz frozen blueberries
4 oz whole milk
4 oz sour cream
10 oz flour
3.5 oz sugar
2 teaspoons baking powder
1/4 teaspoon baking soda
1/2 teaspoon sea salt
1 teaspoon grated lemon zest
1 oz butter, melted
2 tablespoons coarse sugar
INSTRUCTIONS
Adjust oven rack to middle position and heat oven to 425 degrees.
Grate the frozen butter and place back in the freezer until needed.
Whisk together milk and sour cream in medium bowl; refrigerate until needed.
Whisk flour, 1/2 cup sugar, baking powder, baking soda, salt, and lemon zest in medium bowl.
Add frozen butter to flour mixture and toss with fingers until thoroughly coated.
Add milk mixture to flour mixture; fold with spatula until just combined. With rubber spatula, transfer dough to liberally floured work surface.
Dust surface of dough with flour; with floured hands, knead dough 6 to 8 times, until it just holds together in ragged ball, adding flour as needed to prevent sticking.
Roll dough into approximate 12-inch square.
Sprinkle blueberries evenly over surface of dough, then press down so they are slightly embedded in dough. Using bench scraper or thin metal spatula, loosen dough from work surface.
Roll dough, pressing to form tight log. Lay seam-side down and press log into 12 by 4-inch rectangle.
Using sharp, floured knife, cut rectangle crosswise into 4 equal rectangles.
Cut each rectangle diagonally to form 2 triangles and transfer to parchment-lined baking sheet.
Brush tops with melted butter and sprinkle with the coarse sugar.
Bake until tops and bottoms are golden brown, 18 to 25 minutes.
Transfer to wire rack and let cool 10 minutes before serving.
To Make Ahead:
After placing the scones on the baking sheet, either refrigerate them overnight or freeze. When ready to bake, for refrigerated scones, heat oven to 425 degrees and follow directions in step 6. For frozen scones, heat oven to 375 degrees, follow directions in step 6, and extend cooking time to 25 to 30 minutes.