Whisk together the milk, cream, sugar, egg yolks, cornstarch, corn syrup and salt.
Place over medium high heat, stirring occasionally until the mixture starts to steam. Continue to whisk and bring the mixture to a boil. When boiling throughout, remove from heat. Pass through strainer if needed.
Whisk in vanilla and mashed bananas.
Cool off slightly, 5-8 minutes.
Pour into airtight container and chill 8-10 hours.
To freeze, remove from refrigerator and pour into ice cream freezer. Follow the directions with your freezer; each one can vary. My KitchenAid stand mixer (affiliate link) with ice cream maker attachment(affiliate link) takes about 20-25 minutes to freeze fully.
When finished, spoon into airtight container and place in deep freeze an additional 4-6 hours until hardened.