In a saucepan off the heat, combine the sugar, cornstarch and cinnamon. Add the apples and lemon juice. Bring to a boil and cook for about 3 minutes, stirring, until the apples have slightly softened. Cool and refrigerate until completely chilled.
In the bowl of a food processor, combine the flour, sugar, baking powder and salt. Add the butter, eggs and water. Blend until the dough is smooth and forms a ball. With your hands, shape into a disc and refrigerate for about 30 minutes.
In a bowl, combine the sugar and cinnamon. Set aside.
Preheat the oil in the deep fryer to the highest temperature.
Line a baking sheet with paper towels or double with a rack.
On a floured work surface, roll out the dough to a 3-mm (1/8-inch) thickness. Cut into a 46 x 30-cm (18 X 12-inch) rectangle, then cut into 12 rectangles of 15 X 7.5-cm (6 x 3-inch).
Spread about 20 ml (4 teaspoons) of filling at one end of each rectangle to within 1-cm (1/2-inch) of the edge. Brush the edges with the egg white and fold the dough over the apples to form squares. With a fork, press the edges to seal the dough.
Fry about 4 turnovers at a time for 2 to 3 minutes or until they are golden brown on each side. Drain on the sheet. Sprinkle with cinnamon sugar. Serve hot, warm or cold.
Recipes with the "Healthy Pick" stamp have been evaluated by a registered dietitian member of the Ordre professionnel des diététistes du Québec.