Step 1

To make the pastry: Whisk together the flour, salt, and baking powder. Work in the butter until the mixture is crumbly, with some larger, dime-sized pieces of butter remaining. Stir in the sour cream. The dough won’t be cohesive.

Step 2

, Turn the dough onto a floured piece of parchment and bring it together with a few quick kneads. Pat the dough into a rough rectangle, then roll it into an 8” x 10” rectangle.

Step 3

, Flour the dough and fold it in thirds like a business letter. Flip it over, turn 90°, and roll into an 8” x 10” rectangle. Wrap and chill the dough.

Step 4

, To make the filling: Combine all of the ingredients except the egg in a medium saucepan and bring to a simmer; cook until the apples are just barely tender, about 5 minutes. Remove from the heat and cool to room temperature.

Step 5

, To assemble: Roll the pastry dough 1/8” thick. Cut the dough into 5" squares or 6" circles. Stack any scraps on top of each other to re-roll for more pastries.

Step 6

, Place 2 tablespoons of filling in the center of each piece of dough. Brush the edges with some of the beaten egg and fold in half; use the tines of a fork to seal the edges. Place the filled turnovers on a parchment-lined baking sheet. Repeat until all the dough and filling are used. Chill the turnovers while you preheat the oven to 425°F.

Step 7

, To bake: Remove the turnovers from the refrigerator and brush with the remaining beaten egg. Cut three or four slits in the top of each turnover to vent steam. Bake for 22 to 24 minutes, until deep golden brown. Remove from the oven and cool on a rack for at least 20 minutes.

Step 8

, To glaze: Whisk the glaze ingredients together and drizzle over the cooled turnovers.

Step 9

, Store any leftovers, well wrapped, at room temperature for several days; freeze for longer storage.