1Combine filling ingredients in a medium saucepan and cook over medium heat, stirring occasionally, until apples are tender and syrup is thick, about 10 minutes.
2Transfer apple mixture to a plate and chill in the refrigerator until cool to the touch, about 20 minutes.
3Scramble egg and water in a small bowl.
4Place 1 sheet of puff pastry on a clean cutting board; reserve second sheet in the refrigerator.
5Divide pastry into 4 equal squares. Spoon 2 tablespoons apple mixture onto the center of each square.
6Brush the edges of each square with egg wash. Fold pastry diagonally over apple mixture and seal the edges with a fork.
7Place turnovers on a plate and refrigerate while preparing remaining turnovers. Repeat steps 5 to 6 with second sheet of puff pastry.
8Select AIRFRY/325°F/SUPER CONVECTION/20 minutes and press START to preheat oven.
9Place turnovers on airfry rack. Brush tops with egg wash and sprinkle with turbinado sugar. Make 3 small slits in each turnover.
10Cook in rack position 4 until puffed and golden brown, about 20 minutes. Serve warm or at room temperature.
Tip: Use a pizza wheel to easily cut the puff pastry sheets.