Grind 1/2 cups almonds in food chopper or electric blender; mix with flour and 3/4 tsp. salt. Cut in shortening until like coarse meal. Gradually add milk, tossing with fork to form dough. Roll out on floured cloth and fit into 10-inch pie plate. Form a high fluted edge, prick air holes and bake on lowest shelf at 450 degrees 10 to 15 minutes or until golden. Cool. Spread slightly softened ice cream in pie shell; place in freezer. Mix pumpkin with 1 1/2 cups sugar, 1/2 tsp. salt, spices and extract. Whip 1 cup cream until stiff; fold into pumpkin mixture. Turn into shell over ice cream layer. Cover with foil and freeze at least 4 hours. Meanwhile, coarsely chop 1/2 cup almonds; combine with 1/4 cup sugar in small skillet. Place over medium heat; stir constantly and rapidly until sugar is caramelized and almonds are coated. Spread on greased cookie sheet; break apart when cool. At serving time, whip 1/2 cup cream until stiff; spread over pie. Garnish with caramelized almonds. (If pie is frozen very solidly, place in refrigerator a while before serving.)