1. *Make the puff pastry* Fit your food processor with the dough blade, add all the puff pastry ingredients and process until the flour clumps together in large pieces and comes together.
2. Roll out the dough on a floured surface with a floured rolling pin. Make it into a rectangle shape and sprinkle cold unsalted butter (120g) onto the dough (see photo).
3. With the short border of the rectangle closest you, fold the dough into thirds: top and bottom edges to be folded in (see photo). The butter should be enclosed in the dough. Rotate 90 degrees, and roll it out again into a big rectangle with the rolling pin. Fold it again.
4. Wrap the dough in plastic and chill for about 30 minutes or until firm.
5. Repeat steps #3 and #4 twice more. The dough should be smooth by now. Chill it in plastic again for 30 min.
6. *Make the filling* In a frying-pan, melt butter. Add sugar and apple cubes. Cook them on medium-low heat for about 15 to 20 minutes or until wilted. Remove from the heat and let it cool to room temperature. Set aside.
7. *Assemble the cake* Divide the pastry dough in 2 parts, 1/3 and 2/3. Roll out the 2/3rd piece at once and cut into about 25cm circle. Place it on a baking sheet and prick the bottom of the pastry thoroughly with a fork.
8. Roll out the other remaining pastry and cut into strips. Brush the edges of the 25cm circle pastry with water (or beaten egg). Put the pastry strip all around the bottom of the cake to make the border.
9. Then spread the crumbled cookies evenly and spread the apple filling from #6 over the cookies.
10. Make a lattice with the remaining pastry strips over the cake and press gently down to seal well at each strip end. Pre-heat the oven to 200℃.
11. Brush the top of the cake with beaten egg.
12. Bake for 20min. Then lower the heat to 180℃ and bake for another 20min or until nicely browned on top and bottom.
13. Remove the cake from the oven and glaze with apricot jam.
Note : You can bake the remaining pastry into a mini-pie too.