Step 1

Stir together cereal, finely chopped peanuts, and butter in a medium bowl. Press mixture into bottom and up sides of a lightly greased 9-inch glass pie plate. Freeze until solid, 15 to 30 minutes.

Step 2

Microwave peanut butter in a small microwave-safe bowl on HIGH until melted and smooth, about 30 seconds. Let stand at room temperature 10 minutes, stirring occasionally.

Step 3

Place ice cream in the bowl of a heavy-duty stand mixer; beat on medium-low until smooth, about 30 seconds. Drizzle peanut butter into ice cream, beating on low just until incorporated, about 30 seconds.

Step 4

Spread ice cream mixture into frozen pie shell. Cover and freeze until firm, 8 hours, or up to 24 hours.

Step 5

Before serving, remove pie from freezer, and leave out at room temperature 10 minutes. Meanwhile, beat cream and vanilla with an electric mixer on medium-high speed until foamy, about 30 seconds. Gradually add powdered sugar, beating until soft peaks form, 30 seconds to 1 minute. Spread whipped cream evenly over pie. Drizzle with fudge topping, and sprinkle with coarsely chopped peanuts.