01 - Place granulated sugar in a medium saucepan over medium heat. Stir constantly until sugar melts and turns a golden amber color. Add the unsalted butter and continue stirring until fully combined and melted.
02 - Slowly pour in the double cream while stirring, as the mixture will bubble vigorously. Continue stirring until the sauce is smooth. Remove from heat and stir in the sea salt and vanilla extract. Allow the caramel to cool completely.
03 - In a large bowl, use an electric mixer to whip the chilled whipping cream until stiff peaks form.
04 - Gently fold the sweetened condensed milk into the whipped cream until the mixture is fully combined.
05 - Fold 1/2 cup of the cooled salted caramel into the whipped mixture, creating visible streaks if desired. Transfer the mixture into a loaf pan or an airtight freezer-safe container. Drizzle additional salted caramel over the top and swirl lightly with a knife.
06 - Cover the container with plastic wrap or a lid. Freeze for at least 6 hours, or until the ice cream is firm.
07 - Let the ice cream sit at room temperature for 5 minutes before scooping to soften slightly. Serve plain or with extra salted caramel drizzle.