Reese's Peanut Butter Cup Freezer Pie. Only 5 ingredients and 5 minutes prep time before its ready to be frozen. 1 Keebler chocolate cookie pie crust 1 large box of instant chocolate pudding mixed with 1 1/2 milk. Whisk in 1 small tub of Cool Whip. Chop Reese’s Peanut Butter Cups and fold into pudding mix. Pour into crust. Top with more pb cups. Freeze.