Steps
- Measure ¾ cup of dark Jamaican rum. Heat two-thirds in a saucepan over medium-high heat until hot; add 1½ cups of roughly chopped raisins, separate any clumps, and soak off the heat for 30 minutes.
- Drain any unabsorbed rum into a measuring cup and top up with reserved rum to ¼ cup; set aside any excess. Mix this measured rum with 395g of sweetened condensed milk and 1 teaspoon of vanilla extract, then stir in the raisins.
- Beat 2 cups of cold heavy cream on high for 2½-3 minutes, until stiff peaks form. Fold a large scoop into the condensed-milk mixture to loosen it.
- Gently fold that mixture into the remaining whipped cream until smooth. Spread into an 11 × 6 × 3in / 28 × 15 × 7.5cm glass loaf pan, cover, and freeze for at least 12 hours, until firm enough to scoop.