Recipe from Aria Baker.For the dough:
11-1/4 oz. (2-1/2 cups) unbleached all-purpose flour
2 Tbs. granulated sugar
1/2 tsp. kosher salt
6 oz. (3/4 cup) cold unsalted butter, cut into 12 pieces
6 oz. cold cream cheese, cut into 6 pieces
1/2 cup heavy cream

Filling:
3 oz. cream cheese, softened
7 Tbs. granulated sugar
Seeds scraped from 1/2 vanilla bean (or 1/2 tsp. pure vanilla extract)
1 large egg yolk
1 cup blueberries
2 tsp. cornstarch
1/8 tsp. kosher salt

For assembly:
1 large egg yolk
Granulated sugar

Make the dough:
Put the flour, sugar, and salt in a food processor. Add the butter and cream cheese and pulse until the mixture resembles coarse meal, 8 to 10 pulses. Add the cream and pulse, pausing to scrape the bowl once or twice, just until the dough starts to come together, 8 to 10 pulses more. Do not overprocess. Turn the dough out onto a clean work surface, gather it together, and pat it into a rectangle. Wrap it in plastic and refrigerate for at least 2 hours and up to 3 days.

Fillings:
In a medium bowl, combine the cream cheese, 3 Tbs. of the sugar, the vanilla bean seeds (or extract), and 1 egg yolk. Mix with a wooden spoon until well combined and smooth.
Combine the blueberries, 2 Tbs. of the sugar, the cornstarch, and salt in another medium bowl and mix gently.

Assemble and bake the turnovers:
Position racks in the top and bottom thirds of the oven and heat the oven to 400°F.   Line 2 large rimmed baking sheets with parchment.

On a lightly floured surface with a lightly floured rolling pin, roll the dough into a 13x18-inch rectangle. Be sure to loosen the dough several times and re-flour underneath so it doesn’t stick. Trim the edges straight to form a 12x16-inch rectangle and cut the dough into twelve 4-inch squares. Put six squares on each baking sheet.

In a small bowl, beat the egg yolk with 1 tsp. water. Brush the outer edges of each dough square with egg wash.   Dollop 1/2 Tbs. of the cream cheese mixture in the center of each round. Top with 1 Tbs. of the blueberry mixture. Fold in half to form a triangle shape and pinch the edges together to seal them. Lightly brush each pie with egg wash and sprinkle with 1/2 tsp. of the remaining sugar. With the tip of a paring knife, cut a steam vent in the center of each pie.

Bake until the turnovers are browned and the filling is bubbling, 25 to 30 minutes, swapping and rotating the baking sheets’ positions about halfway through baking. (Don’t worry if juice leaks out.)

Transfer the baking sheets to racks and allow to cool for 5 minutes. Then loosen the turnovers with an offset spatula and cool completely on the sheets. The turnovers are best the day they’re made.

Ingredients:
8 tbsp. (1 stick) unsalted butter, frozen whole
1½ cups (7½ oz.) fresh blueberries
½ cup whole milk
½ cup sour cream
2 cups (10 oz.) all-purpose flour, plus more for dusting the work surface
½ cup sugar, plus extra for sprinkling
2 tsp. baking powder
¼ tsp. baking soda
½ tsp. salt
1 tsp. finely grated lemon zest
2 tbsp. unsalted butter, melted

Directions:
Adjust an oven rack to middle position and preheat to 425˚ F.  Grate the frozen butter on the holes of a large box grater.  (I like to use my food processor for this – fast and easy.)  Place the blueberries in the freezer until needed.

Whisk together the milk and sour cream in a medium bowl; refrigerate until needed.  Combine the flour, ½ cup sugar, baking powder, baking soda, salt and lemon zest in a medium mixing bowl.  Whisk to combine.  Add the grated butter to the flour mixture and toss with fingers until thoroughly coated.

Add the milk mixture to the dry ingredients and fold with a spatula just until combined.  Transfer the dough to a generously floured work surface.  Dust the top of the dough with flour, and knead with well floured hands, 6-8 times, just until the dough holds together in a ragged ball.  Add small amounts of flour as needed to prevent sticking.

Roll the dough into a 12-inch square.  Fold the dough into thirds like a business letter (a dough scraper really helps with these steps).  Fold the short ends of the dough into the center in thirds, to form an approximate 4-inch square.  Transfer the dough to a plate lightly dusted with flour and chill in the freezer for 5 minutes.

Return the dough to the floured work surface and roll into an approximately 12-inch square again.  Sprinkle the blueberries evenly over the surface of the dough, and gently press down so that they are slightly embedded in the dough surface.  Using a dough scraper, roll the dough up to form a tight log.  Lay the log seam side down and press the the log into a 12 by 4-inch rectangle.  Using a sharp, floured knife, cut the rectangle crosswise into 4 equal rectangles.  Cut each rectangle diagonally to form 2 triangles.  Transfer to a parchment lined baking sheet.

Brush the tops of the scones with melted butter and sprinkle lightly with sugar.  (If freezing ahead of time, flash freeze on the baking sheet for 20 minutes, then wrap individually and store in a freezer bag until needed.)  Bake until the tops and bottoms are golden brown, 18-25 minutes.  Transfer to a wire rack and let cool at least 10 minutes before serving.

Crust Ingredients:
2 cups all-purpose flour
1/4 teaspoon salt
2/3 cup cold butter
4 to 5 tablespoons cold water