Invert the base of a 23cm springform tin, and grease and line it with baking paper. Put biscuits in a food processor and process until fine crumbs form. Add melted butter and process until combined. Press mixture evenly into the base of tin. Freeze while preparing ice-cream.
Allow ice-cream to soften – but not melt – out of the freezer for 20-25 minutes. Whisk Fruche in a large bowl until smooth. Add softened ice-cream and meringue and stir until combined.
Spoon onto frozen biscuit base and smooth the top. Tap tin on bench a few times to settle mixture. Cover with plastic wrap and freeze overnight.
Run a metal spatula around the edge of cake to loosen. Unclip tin and remove cake. Transfer to a serving platter and pour caramel on top. Use spatula to gently push some caramel close to the edge so it drizzles over. Return to freezer.
When ready to serve, sprinkle with combined pistachios, macadamias and coconut. Serve immediately.
Tip: You can make this cake, without caramel topping, up to four days before you intend to serve it.