In a small bowl beat cream cheese and 2 tablespoons dulce de leche with an electric mixer on medium to high speed for 30 seconds. Add 1 egg and 3 tablespoons sugar; beat on medium speed until smooth. Cover and chill for 30 minutes.
Meanwhile, preheat oven to 350 degrees F. Prepare Hazelnut Pastry. On a lightly floured surface, roll pastry into a 12-inch circle. Ease pastry circle into a 9-inch pie plate without stretching it. Spoon cream cheese mixture into pastry-lined pie plate. Trim pastry to 1/2 inch beyond outside edge of pie plate. Fold under extra pastry. Crimp edge as desired.
In a medium bowl whisk together pumpkin, evaporated milk, 2 eggs, 1/3 cup sugar, 2 tablespoons dulce de leche, hazelnut liqueur (if desired), and pumpkin pie spice. Carefully pour pumpkin mixture over cream cheese mixture.
Cover edge of pie loosely with foil. Bake for 25 minutes, remove foil. Bake about 25 minutes more or until filling is set in the center. Cool on a wire rack.
To serve, top pie with Dulce de Leche Hazelnut Whipped Cream, sprinkle with hazelnuts (if desired), and drizzle with additional dulce de leche (if necessary, warm or stir in a little milk to thin for drizzling).
Dulce de Leche Hazelnut Whipped Cream
Place dulce de leche in a chilled small mixing bowl. If desired, add hazelnut liqueur. Beat with the chilled beaters of an electric mixer on medium to high speed until smooth. Add whipping cream. Beat on medium speed just until stiff peaks begin to form.
In a mixing bowl, stir together all-purpose flour, hazelnuts, and salt. Using a pastry blender, cut in shortening until pieces are pea size. Sprinkle 1 tablespoon of cold water over part of the mixture; gently toss with a fork. Push moistened dough to the side of the bowl. Repeat moistening dough, using 1 tablespoon cold water at a time, until all the dough is moistened (4 to 5 tablespoons cold water total). Form dough into a ball.