In a medium stock pot combine heavy whipping cream, sugar, and egg yolks. Heat on medium until mixture starts to bubble. Add 1/2 cup of peanut butter and continue cooking for 7 minutes.
Remove from heat and add vanilla. Mix until glossy in appearance. Add 1/2 of the Cool Whip.
Spoon 1/2 cup of remaining peanut butter in the bottom of the pre baked pie crust. Pour peanut butter custard mixture into pie shell. Top with remaining Cool Whip.
Garnish with chocolate syrup and chopped Reese's Peanut Butter cups.
Chill for at least 2 hours.