STEP ONESTIR flour and salt in large bowl until blended. Cut shortening into flour mixture using pastry blended or fork until shortening pieces are the size of peas. While stirring with fork, add ice water, 1 tablespoon at a time, just until dough holds together and forms a smooth ball. Flatten into a 1/2-inch thick disk. Wrap in plastic wrap. Chill at least 30 minutes or up to 2 days.
STEP TWOHEAT oven to 425°F. Roll dough into an 11-inch circle on lightly floured surface. Transfer dough to 9-inch pie plate. Trim and flute edges, as desired.
STEP THREEBAKE 15 to 20 minutes or until lightly browned. Cool completely on wire rack.
STEP FOURFor Filling, BEAT cream in medium bowl with mixer on high speed until stiff peaks form. Set aside.
STEP FIVEBEAT cream cheese, peanut butter, sugar, butter and vanilla in large bowl with mixer on high speed until smooth. Fold in whipped cream until evenly blended. Stir in 3/4 cup peanut butter cups.
STEP SIXSPOON into cooled pie crust. Sprinkle with remaining peanut butter cups. Chill several hours before serving.