Prepare the Pie Dough:

1. Preheat oven to 400 F.
2. Roll out 3 pieces of easy puff pastry pie dough to approximately 12-inches. The extra third pie dough is used for braiding the lattice (which requires a lot of pie dough) and for the decorative leaf cutouts.

Prepare the Apple Pie Filling:

1. Whisk together butter, sugar, water and flour in a mixing bowl. Transfer the mixture to a small saucepan and bring to a boil over medium heat. Stir continuously for 2 minutes until it forms a smooth mixture. Remove from heat and set it aside. The sauce will be thick and more like a paste.
2. Place the peeled, cored and sliced apples into a large mixing bowl. Add cinnamon and stir with a silicone spatula to coat the apple slices evenly.
3. Pour the prepared sauce mixture in and stir to coat the apple slices well. Set the bowl aside.

Assemble the Pie:

1. Transfer one prepared dough disc onto a 9-inch pie pan and gently press down to form into the bottom pie crust.
2. Slowly pour the apple filling from the bowl into the dough-lined pie pan and use a spatula to spread them evenly across. 

Create the Braided Lattice Top:

1. Make the braided strips: Slice the second pie dough into 15 strips, measuring 1/2-inch wide. Save the leftover dough scraps to the side. Take 3 strips of equal length and squeeze the 3 ends together. Braid them together by moving the left strip across the middle strip. Then, move the right strip across the middle strip. Repeat the left and right to the middle until you reach the end of the braid. Squeeze to bind the 3 ends together. Repeat the braiding will the remaining strips, until you have 5 braided strips.
2. Make the flat lattice strips: Slice the 3rd dough circle into 5 strips, measuring 1-inch wide. Save the dough scraps to the side.
3. Place 5 flat lattice strips of dough on top of the apple filling, evenly placed 1-inch apart (make sure to use the longer strips in the centre and shorter strips for the edges).
4. Fold back the 2nd and 4th strip halfway and place the longest braided strip in the centre, perpendicular to the first 5 strips. Place the 2nd and 4th strip back over that long strip.
5. Fold back the 1st and 3rd and 5th strip halfway and place a slightly shorter braided strip 1-inch away. Place the 1st and 3rd and 5th strip back over the shorter strip.
6. Continue adding and alternating braided strips to complete the lattice top crust.
7. Take the dough scraps and cut out decorative leaves and place them on top of the lattice pie.
8. Press edges together and crimp with your fingers to seal. You can place more scraps along the edge and pinch them into the edges to seal.

Bake the Pie:

1. Combine beaten egg and milk in a small bowl (egg wash). Brush the egg wash over the lattice crust and edges. If your oven is not ready at this point, store the assembled pie in the fridge to prevent the pie crust from disintegrating (the butter in the dough melts quickly at room temperature).
2. Transfer the apple pie into a 400 F preheated oven and bake for 20 minutes until the edges of the pie start turning golden brown. Reduce the oven temperature to 350F and bake for additional 40 minutes until the pie crust is golden brown. You might see the pie fillings ooze out.
3. Leave the apple pie in the pan at room temperature and allow it to cool down and set before serving (1 hour). You can serve it immediately if you can't wait but the filling will be more soft. Serve a slice of apple pie with a scoop of vanilla ice cream.