In a small saucepan, combine milk and brown sugar; cook and stir over medium heat until brown sugar is dissolved. Cool to room temperature., In a large bowl, beat cream cheese and peanut butter until blended. Gradually add milk mixture, cream and vanilla; beat until smooth. Press plastic wrap onto surface of mixture. Refrigerate several hours or overnight., Pour half of the cream cheese mixture into cylinder of ice cream freezer; freeze according to manufacturer’s directions, adding half of the chopped cookies and half of the peanuts during the last 2 minutes of processing. (Refrigerate remaining mixture until ready to freeze.) Transfer ice cream to a 9-in. springform pan., Repeat with remaining cream cheese mixture, cookies and peanuts. Transfer to pan. Freeze until firm, about 4 hours., To serve, remove rim from pan. Drizzle ice cream with chocolate and caramel toppings. If desired, serve with whipped cream.