Grease the base of a 20cm springform cake pan.

Process malt biscuits in a food processor to fine crumbs.

Add melted butter to the biscuit crumbs and combine.

Press the crumb mixture into the base of the pan.

Refrigerate for 30 minutes or until firm.

Combine milk, marshmallows, and chopped dark chocolate in a heatproof bowl.

Place the bowl over a saucepan of simmering water and stir until smooth.

Remove the bowl from the pan.

Combine unflavored gelatin powder and 1 tablespoon of cold water in a heatproof cup.

Stand the cup in simmering water and stir until the gelatin is completely dissolved.

Stir the dissolved gelatin into the chocolate mixture.

Cool the mixture for 30 minutes.

Gently fold whipped thickened cream into the cooled chocolate mixture.

Pour the mixture over the biscuit base.

Cover and refrigerate for 4 hours or until set.

Spread extra whipped cream over the pie.

Top with chocolate shavings to serve.