In a medium saucepan, combine butter and brown sugar. Cook over medium heat until butter is melted and mixture is smooth; stir frequently. Refrigerate 10 minutes.
In large bowl, beat peanut butter and brown sugar mixture at LOW speed until blended. Increase speed and beat 1 minute at HIGH speed. Reduce speed to LOW and add whipped topping; beat one additional minute.
Pour into graham crust and refrigerate for several hours before serving.
In a medium saucepan, combine butter and brown sugar. Cook over medium heat until butter is melted and mixture is smooth; stir frequently. Refrigerate 10 minutes.
In large bowl, beat peanut butter and brown sugar mixture at LOW speed until blended. Increase speed and beat 1 minute at HIGH speed. Reduce speed to LOW and add whipped topping; beat one additional minute.
Pour into graham crust and refrigerate for several hours before serving.