Add the sugar to a heavy-bottomed saucepan, then pour the water over it until all the sugar is wet.

Cook over medium-high heat without stirring, as using a spoon can cause crystallization. Gently swirl the pan occasionally if needed.

Once the sugar reaches a golden-amber color, immediately add the cream, whisk until combined and cook for 1-2 minutes until the caramel thickens slightly.

Take it off the heat, then mix in the butter and salt and whisk until fully combined. I highly recommend blending the caramel once it has cooled for a smooth, shiny sauce.

Combine the whipping cream, condensed milk, melted milk chocolate, and cocoa powder in a large bowl. Whip on high speed for 3-5 minutes until thick and creamy.

Line a loaf pan with baking paper, leaving an overhang on both sides.

Arrange the shortbread cookies in a single, even layer across the base of the pan.

Spread the caramel sauce evenly over the shortbread layer, then refrigerate for 15 minutes to set the layers before adding the ice cream.

Spoon the chocolate ice cream on top and smooth it out with an offset spatula. Cover tightly and freeze for at least 8 hours, or overnight for best results.

When fully frozen, lift the ice cream bar out of the pan using the baking paper overhang.

Melt the milk chocolate using a double boiler, or microwave in 30-second bursts, stirring between each interval, until completely smooth.

Allow it to cool slightly; you don't want it too hot, or it'll melt the ice cream. Pour it over the bar and use an offset spatula to coat all sides quickly. The chocolate sets on contact, so be quick.

Return the bar to the freezer for 10 minutes until the shell is fully set. Slice and serve straight from the freezer.