Turn the pastry out onto a work surface, and knead very gently to bring the dough together. Form the dough into a disk shape, wrap in plastic wrap, and refrigerate for at least 1 hour. Two is even better.
Preheat oven to 350 degrees F.
Using a light dusting of flour on your board and rolling pin, roll out the dough to the desired thickness. Lay the dough into the pie plate, and prick with a fork all over, trim and decorate the edge of the pie as you wish.
Filling: In a large bowl, combine the maple syrup, egg, sugar, and cream, and stir well to mix. Transfer the filling mixture to the pastry-lined pie dish. Top with the pecan nuts, and bake for about 35 minutes, or until set. Let cool before serving.