In a medium bowl, mash the bananas until they are completely smooth.
In a saucepan, combine the mashed bananas, milk, sugar, egg yolks, cornstarch, butter, vanilla extract, and salt. Heat over medium heat, stirring constantly, until the mixture thickens and starts to bubble, about 10 minutes.
Remove from the heat and let cool for 10 minutes.
Transfer the mixture to an ice cream maker and freeze according to the manufacturer's instructions.
Transfer the ice cream to an airtight container and freeze until firm, about 2 hours.
Interesting Facts
Bananas are a good source of potassium, which helps to regulate fluid balance in the body.
The cornstarch in this recipe helps thicken the ice cream and gives it a creamy texture.
Vanilla extract adds a subtle sweetness to the ice cream.