Put the cornstarch in a small bowl and add 2 tablespoons of milk. Set aside.
Put the remaining milk in a heavy-bottomed saucepan, along with the cream, sugar, corn syrup, and vanilla bean. Bring the mixture to a boil and boil for 4 minutes.
Off heat, stir in the cornstarch paste. Return the pan to the heat and boil for one more minute, whisking constantly.
Take the pan off the heat and remove the vanilla bean.
Put the cream cheese in a medium-sized mixing bowl and gradually whisk in the hot milk mixture.
Add the salt, and if using vanilla extract in place of the bean, add that now.
Set the bowl in a pan of ice water to cool, or if you’re not pushed for time, put it in the fridge to chill.
Freeze the ice cream according to your maker’s directions.