Line base and sides of a deep, 20cm square cake pan with baking paper, allowing 5cm overhang on all sides.
Place Bulla Chocolate Ice Cream in a large bowl of electric mixer and beat on low speed for 1 minute or until softened. Fold through crushed biscuits. Spoon half of the chocolate ice cream mixture into prepared pan. Spread evenly and smooth surface, place in freezer. Refrigerate remaining chocolate ice cream while preparing the next layer of the cake.
Spoon Bulla Vanilla Ice Cream into a large bowl of electric mixer and beat on low speed for 1 minute or until softened. Fold in chopped Clankers. Spoon on top of chocolate ice cream layer and smooth surface. Carefully spoon the remaining chocolate ice cream, over this layer, again smooth the top. Cover well and freeze overnight until firm.
Invert onto a serving plate, peel off paper and decorate with lollies.