• Preheat oven to 400°F and line 2 baking sheets with parchment paper. Set aside.

MAKE FILLING

• To a saucepan, add butter and heat over MED heat. Add apples, brown sugar, cornstarch, cinnamon, nutmeg, salt and vanilla extract and stir to combine.
• Bring to a low boil, then reduce heat to LOW and simmer until thickened, about 3-5 minutes.
• Set aside to cool COMPLETELY.

ROLL OUT DOUGH

• Lightly flour a work surface (I use my counter) and add thawed puff pastry sheet. Sprinkle with a bit more flour and roll out to a roughly 11-12 inch square.
• Use a pizza cutter, pastry wheel, sharp knife or bench scraper to cut dough into 8 equally sized rectangles.
  

ADD FILLING, EGG WASH, AND COVER

• Once filling has completely cooled, spoon apple filling in the center of each rectangle, making sure to leave a 1/2 inch border on all sides.
• Whisk together egg and water and brush mixture around the border of each rectangle.
• Roll out second pastry sheet to the same size as the first one (11-12 inch square), then slice into the same 8 equally sized rectangles.
• Top each apple covered dough rectangle with another dough rectangle and press together. Use the tines of a fork to crimp the edges.

BAKE

• Transfer turnovers to prepared baking sheets, leaving some room in between each one. Brush with egg wash.
• Bake for 20-25 minutes, until golden brown and puffed.

COOL AND TOP

• Transfer turnovers to a wire rack to cool, the filling will be piping hot.
• Dust with powdered sugar, or top as desired.