1. Peel and dice apples.
2. Stir water and baking powder together in a small bowl.
3. Combine the baking powder-water mixture, butter, brown sugar, cinnamon, nutmeg, and salt in a medium-size skillet over medium-high heat.
4. Whisk together until combined and mixture has become thick and bubbly.
5. Add apples and stir until they are fully coated and tender.
6. Lay the pastry out and flatten with a rolling pin so that it is about ¼-inch (6cm) thick throughout.
7. Preheat oven to 375°F (190°C).Slice pastry into 6 rectangles using a sharp knife or fancy rotary cutter.
8. Spoon apple mixture onto top 6 rectangles. Dip your finger in water and line the outer rim of each rectangle. Fold over the pastry and press lightly to seal.
9. If desired, use a fork and press the sides around each rectangle to seal the filling in.
10. Whisk an egg and brush it over the top of each pie with a pastry brush, then place them on a greased baking sheet.
11. Using a knife, make 3 or 4 slits in each pie.
12. Bake for 20-25 minutes or until golden brown.
13. Let cool for at least 10 minutes before enjoying.
