In a small bowl, whisk together flour, pumpkin pie spice, and baking soda.
In a medium bowl, with an electric mixer, cream butter and sugar. Beat in pumpkin pie purée. Beat in eggs and vanilla. Beat in flour mixture until just combined. Stir in white chocolate and pecans.
Drop dough by rounded tablespoons 2 inches apart on an ungreased cookie sheet. Bake at 300 degrees F (150 degrees C) for 20 to 22 minutes until just set.