Creating French Apricot Pastry is simple if you follow these steps:

1. Preheat the Oven: Preheat your oven to 375°F (190°C).
2. Prepare the Crust: In a bowl, mix the flour, sugar, and salt. Add the diced butter and mix until the mixture resembles coarse crumbs.
3. Add Water: Gradually add cold water, one tablespoon at a time, until the dough comes together.
4. Chill the Dough: Shape the dough into a disk, wrap it in plastic wrap, and refrigerate for at least 30 minutes.
5. Prepare the Filling: In another bowl, combine the apricot preserves, vanilla extract, and lemon juice.
6. Roll Out Dough: On a floured surface, roll out the chilled dough into a rectangle, about 1/8 inch thick.
7. Cut the Dough: Cut the dough into squares or rectangles, depending on your preference for pastry size.
8. Fill the Pastry: Place a spoonful of the apricot mixture in the center of each piece of dough.
9. Fold the Pastry: Fold the edges over the filling, sealing them well. You can crimp the edges with a fork for a decorative touch.
10. Egg Wash: Beat the egg and brush it over the top of each pastry to give it a golden color.
11. Bake: Place the pastries on a baking sheet lined with parchment paper and bake for 30-35 minutes or until golden brown.
12. Cool: Once baked, remove from the oven and allow to cool on a wire rack for 15-20 minutes.
13. Dust with Powdered Sugar: Optionally, dust with powdered sugar before serving.

Following these steps will guide you in creating this incredible French Apricot Pastry effortlessly.