Vanilla-Pecan Ice Cream Torte

Preheat oven to 375 degrees F. Reserve 16 pecan halves for garnish. In food processor with knife blade attached, blend remaining pecan halves with gingersnaps and sugar until mixture is finely ground. In 9-inch springform pan, with fork, stir cookie mixture and melted margarine or butter until moistened. With hand, press mixture onto bottom of pan. Bake crust 8 minutes. Cool completely on wire rack. Let ice cream soften on counter 20 minutes. In large bowl, mix softened ice cream and pumpkin-pie spice until blended; spread over crust. Place pecan halves around top edge of torte. Cover torte and freeze at least overnight or up to 1 week. To serve, let frozen torte stand at room temperature about 15 minutes for easier slicing. Remove side of springform pan.