Line a greased 9 x 13 pan with Club Crackers. Boil butter, sugar, brown sugar, cracker crumbs and milk on medium heat for 5 minutes, stirring constantly. Pour half of mixture on crackers in pan. Cover with a layer of Club Crackers. Pour on remaining mixture. Top with a layer of Club Crackers. For frosting: Melt chips and peanut butter together until smooth. Spread over top of bars. Refrigerate until set.