Heat the oven to 400°F. Beat the egg and water in a small bowl with a fork.
Sprinkle the flour on the work suface. Unfold the pastry sheet on the work surface. Roll the pastry sheet into a 12-inch square. Cut into 4 (6-inch) squares. Brush the edges of the pastries with the egg mixture.
With a corner of 1 pastry facing you, place 2 slices ham and 1 slice cheese on the bottom half of the pastry. Fold the pastry over the filling to form a triangle and press the edges to seal. Crimp the edges with a fork. Repeat with the remaining pastries. Brush the pastries with the egg mixture. Place the pastries onto a baking sheet.
Bake for 20 minutes or until the pastries are golden brown. Sprinkle the pastries with the confectioners’ sugar. Serve with the maple syrup.
Mothers Secret Recipes of Comfort Food & Culinary Inspiration from an Organic and Allergen-free Approach