Start by peeling, coring and chopping the apples and pears.
In a saucepan, heat the butter until it melts. Add the chopped apples and pears, followed by the cinnamon, brown sugar and lemon zest.
Cook on medium heat, until the apples are softened, around 7-8 minutes.
Add the flour and mix well. Turn off the heat and let the mixture cool down completely.
Prepare the puff pastry sheets -roll the out and cut into 8 squares.
Place 2 tablespoons of the filling in the center of each rolled sheet of puff pastry. Using a brush, brush some fo the egg wash around the filling.
Fold each square into a triangle, using a fork to seal together the edges of the pastry.
Brush some of the egg wash on the top of the puff pastry, sprinkle some of the raw cane sugar over the puff pastry and transfer toa baking sheet lined with aluminum foil or baking paper.
Bake in a preheated oven at 350 F for 15 minutes, until the puff pastry is crispy and golden.
Let the turnovers cool and serve.