Heat the oven to 350°F. Line a baking sheet with parchment. Spread the chopped pecans on one side. Toss the pecan halves with 1 tablespoon maple syrup and a pinch of salt and spread them on the other side. Bake 8 to 10 minutes, until fragrant. Cool completely.
Raise the oven to 400°F. Fit the crust into a 9-inch deep-dish pie plate, crimp the edge, prick the bottom with a fork and freeze 15 minutes.
Line the crust with parchment and fill to the top with pie weights or dried beans. Bake 15 minutes. Remove the parchment and weights and bake 10 to 12 minutes more, until the bottom is dry and golden. Cool completely, about 1 hour.
Beat the cold cream and powdered sugar to stiff peaks. Refrigerate.
Beat the softened cream cheese until smooth, about 1 minute. Add the brown sugar, ¼ cup maple syrup, vanilla and ¼ teaspoon salt and beat 2 minutes, scraping the bowl, until completely smooth.
Fold in the whipped cream in two additions, then fold in the toasted chopped pecans.
Spread the filling in the cooled crust. Refrigerate at least 4 hours or overnight, until firm.
Shortly before serving (up to 4 hours ahead), arrange the maple pecan halves on top. Slice with a sharp knife dipped in hot water and wiped dry.