Preheat the oven to 170C. 

For the cookie crumb crunch add the milk powder, flour, cornflour, sugar and salt in a bowl. Add the melted butter and toss to combine until small clusters form. Spread the clusters on a baking tray lined with baking paper and bake for 15 minutes or until just golden. Remove and allow to cool.

Once cooled add to a bowl with the coating ingredients and stir until the crumbs and clusters are coated. Spread out on a tray to allow the chocolate to harden and the crumbs are no longer sticky. Combine with the toasted macadamia and set aside. 

For the Anzac biscuit base, place the flour, oats, sugar and coconut in a large bowl and stir to combine.

In a small saucepan place the golden syrup and butter and stir over low heat until the butter has melted and remove from the heat.

Mix the bicarbonate soda with 1½ tablespoons water and add to the golden syrup mixture. Pour into the dry ingredients with the egg yolk and mix together until fully combined.

Grease and line a high-sided (15cm) baking tray (20cm x 30cm). Press the mixture into the base, pressing down to flatten slightly, then place in the oven for 10 to 12 minutes or until just golden brown.

Add the softened ice-cream and malt syrup to a bowl and stir to combine. You only want to just mix the malt syrup through so it creates strands of caramel through the ice-cream.

Pour the ice-cream onto the Anzac biscuit base then tightly cover the tray with plastic wrap and place in the freezer overnight or until ice-cream is firm.

To serve, gently remove from the baking tray, scatter the macadamia cookie crumb and drizzle with dulce de leche (if using). Slice into rectangles with a hot, wet knife and serve immediately