1.Reserve 2 peppermint crisp bars. Using a small, sharp knife, coarsely chop the remaining peppermint crisp bars and place in a small bowl.
2.Grease a 20cm square cake pan, then line base and sides with baking paper, extending paper 5cm above edges.
3.Scoop ice-cream into a large bowl. Set aside to soften slightly. Gently fold in the chopped peppermint crisp. Evenly spread ice-cream mixture into pan. Using the back of a spoon, smooth the top. Cover ice-cream directly with plastic wrap and freeze for 4 hours or overnight until frozen.
4.Using the paper tabs as an aid, lift the ice-cream slab from the pan and place on a chopping board. Cut slab into eight 5cm x 10cm rectangles and place on a tray. Cover tray with plastic wrap and return to the freezer.
5.Preheat oven to 180ºC/160ºC fan-forced. Grease two 20cm square cake pans, then line bases and sides with baking paper, extending paper 5cm above edges.
6.Coarsely chop butter and chocolate. Place butter and chocolate in a microwave-safe bowl. Microwave on HIGH in 30-second bursts, stirring, until melted and smooth. Transfer mixture to a large bowl. Cool for 10 minutes.
7.Stir sugar and eggs into cooled chocolate mixture. Sift over flour. Stir until combined. Divide mixture evenly between pans.
8.Bake brownies for 25 minutes or until a skewer inserted into the centre comes out with moist crumbs attached. Remove pans from oven. Leave brownies in pans.
9.Coarsely chop reserved peppermint crisp bars. Sprinkle the top of one brownie evenly with the chopped peppermint crisp, pressing in gently to secure.
10.Using the paper tabs as an aid, lift the brownies from the pan and place on a chopping board. Cut each brownie into eight 5cm x 10cm rectangles to make 16 fingers in total.
11.When ready to serve, assemble the ice-cream fingers. Place eight plain brownie fingers on a tray, top each with an ice-cream rectangle, then a peppermint-crisp-topped brownie finger. Serve straight away.
You will need to make the ice-cream slab and the brownies a day ahead. However, it is best to assemble the ice-cream fingers just before serving.