For the Pie Crust:
In the bowl of a food processor, mix together flour and salt. Cube butter and place on top of the flour mixture. Blend the butter into dry ingredients in short bursts until pea-sized pieces are scattered throughout. Add ice cold water 1 tablespoon at a time through the feed tube while processing in short bursts. Keep pulsing until a shaggy ball is formed to one side of the bowl. Turn out dough and shape into a flat disk. Cover with plastic wrap and refrigerate for at least 1 hour.
Preheat oven to 450°F.
Roll the pie dough disk into a 12-inch circle and fit in the bottom of a 9-inch pie plate. Trim pastry to 1/2 inch beyond the edge of the plate and crimp the edges. Line the dough with parchment paper and add dry rice or pie weights. Bake for 8 minutes then cool on a wire rack.
For the Maple Caramel Walnut Pie Filling:
In a large saucepan, combine the brown sugar, syrup, butter, cream and salt. Bring to a bubble over medium heat stirring constantly. Remove the pan from heat and let cool 12 minutes.
Preheat oven to 350°F.
In a large bowl beat together the eggs and maple extract. Gradually add the syrup mixture to the eggs in a thin stream while whisking constantly to temper. Stir in chopped walnuts; pour into the prepared pie crust. Arrange walnut halves on top of the pie filling. Bake the pie for 40-45 minutes or until well set. Cool on a wire rack. Serve with whipped cream.