2 1/4 c. heavy cream
1 1/4 c. creamy or chunky peanut butter
1 c. confectioners' sugar
1 c. (about 15) miniature peanut butter cups, unwrapped and chopped, plus 6 peanut butter cups, unwrapped and halved
1 prepared 9-inch chocolate crumb piecrust

In small saucepan, heat together 1/4 c. heavy cream, the peanut butter and 1/4 c. confectioners' sugar over medium heat, stirring until smooth. Remove from heat; let cool to room temperature. Meanwhile, beat together remaining 2 c. heavy cream and remaining 3/4 c. confectioners' sugar until stiff peaks form. Fold cooled peanut butter mixture into whipped cream along with chopped peanut butter cups. Spoon into prepared crust. Top with peanut butter cup halves. Freeze until semi-frozen, about 3 hours. Cut into 12 slices and serve.