Pre-heat the oven to 400° and line a baking sheet with parchment paper.
Roll out the puff pastry on a lightly floured work surface to form a large square - this does not have to be perfect! Transfer the rolled out puff pastry to the prepared baking sheet. Don’t worry if some of it overlaps over the sides of the baking sheet, you’re going to be folding it inwards soon!
Mix together the pecans and chopped chocolate and place all of it in the centre of the puff pastry. Spread it out leaving about about an inch or so of uncovered pastry.
Begin gently folding over the edges of the dough to create overlapping pattern.
In a medium sized bowl mix together melted butter, brown sugar, maple syrup, beaten egg and salt. Carefully pour this mixture evenly over the chocolate and pecans.
Brush the pastry with an egg wash, and sprinkle over with the demerara sugar.
Bake for 30 minutes, or until the pastry has turned a deep golden brown. Enjoy!