1. For the ice-cream, combine cream and condensed milk in the basin of a stand mixer and whip until thick and fluffy. You can also do this with electric beaters. If you don't have either, whip the cream by hand to soft peaks, then fold through the condensed milk with the whisk. Transfer to a freezer-proof container and freeze until solid, at least 4 hours.

2. For the crumble, heat your oven to 180C. Place the biscuits in a plastic bag and lightly crush them. Combine with the brown sugar and butter and spread the mixture on a lined baking tray. (If using sweet biscuits, you can reduce the brown sugar by half.) Scatter with the white sugar and salt. Bake for 10-15 minutes until well toasted. Cool, then break the crumble up so that it can be scattered. Scatter the crumble onto scoops of ice-cream to serve.

Adam's tip: You can fold the crumble through the ice-cream before freezing if you prefer. For a real short cut, just buy good vanilla ice-cream and fold the crumble through that. It's not cheating, it's smart!