In a food processor, purée the chopped mangoes, fresh lime juice, light corn syrup and salt until very smooth.

Pour the mixture into a bowl and set aside.

Set up an ice water bath with a large bowl one half full of icy water with a smaller bowl set on top of the ice. Place a sieve on the top bowl.

In a heat resistant medium bowl, whisk together the egg yolks, granulated sugar, cornstarch and the ¼ cup whole milk until the mixture becomes light yellow and the sugar has dissolved. This should take approximately 1-2 minutes.

In a medium saucepan, heat the ¾ cup whole milk until it comes just below the boil.

Slowly whisk the hot milk into the egg mixture.

Pour the mixture back into the saucepan and place over medium heat. Whisk the mixture constantly until it thickens slightly. The custard should coat the back of a spoon and leave a path as you pull your finger across it.

Pour the custard through the sieve set over the top bowl of the ice water bath. Remove the sieve without pressing down on the solids that remain.

Whisk the zest, rum and heavy cream into the mixture until well blended. Allow to cool.

Cover the bowl and place in the refrigerator for several hours or overnight to get very cold.

Process the mixture in an ice cream maker of your choice.

Freeze the ice cream in an airtight container in the freezer overnight, before serving.