Set up your ice cream machine (most devices require the bowl to be in the freezer for 24 hours before making ice cream).
In a small saucepan over medium-low heat, combine the sugar, heavy cream, milk, 1 whole plantain, vanilla seeds, vanilla pod, ½ teaspoon salt and bring it to just below simmering. Before it simmers, stir, and turn off the heat.
In a large bowl, whisk your egg yolks. Temper the eggs by slowly pouring in a small amount of the warm milk mixture while mixing continuously. Once 1 cup of the milk has been slowly incorporated, add all of the milk mixture.
Pour the mixture through a fine mesh strainer back into the saucepan that contained the milk. Heat the custard over medium heat until it reaches 180 degrees or thickens enough to coat the back of a spoon.
Strain the mixture again into a bowl and chill for at least 4 hours in the fridge.
Pour the mixture into your ice cream machine and follow the manufacturer’s instructions.
Mix in the ½ cup of coconut and place the ice cream into a freezer-safe, lidded container and freeze for at least 4 hours.
When ready to serve, make the topping. Melt the butter and brown sugar in a large frying pan. Toss in the plantains and salt and simmer for about 10 minutes until the plantains look soft and the liquid appears syrupy.
Pour the hot sweet plantains over the ice cream and serve immediately.