Combine the heavy cream, milk, sugar, corn syrup and salt in a medium saucepan. Bring the mixture to a simmer, whisking regularly to dissolve the sugar. Remove the pan from the heat and stir in the vanilla extract and rum or vodka (if using).

Add the mashed bananas to the cream mixture and stir until combined. Refrigerate and cool completely for at least 4 hours or overnight. If you don’t want to wait until tomorrow to make the ice cream, cool the ice cream base in a bowl resting in an ice bath and stir often to cool it quickly.

When the mixture has completely cooled, pour it into an ice cream maker. Churn the mixture according to the manufacturer’s instructions. When the mixture reaches soft serve set, stir in the chocolate chunks and the walnuts.

Serve soft serve style or transfer to a container and freeze for at least 2 hours for a harder, scoopable texture.