Cut the bananas into 3/4" thick and set aside.
Using a wide pan melt the butter over medium heat then add the bananas flat side down, allow to cook for about 3-4 minutes until browned.
With a fork turn the bananas slices the other side for an even brown.
Add the sugar and salt to the bananas, once the sugar has melted add the heavy cream and gently stir.
In a small bowl mix the cornstarch with the water and mix to blend.
Add cornstarch to the banana mix, reduce heat to low, and continue stirring until the mix has thickened while stirring. About 1-2 minutes.
Remove from heat and allow to cool.
In a large bowl pour the condensed milk.
Whip heavy whipping cream to a stiff pick and gently fold 3/4 into the sweetened condensed milk.
Fold in the caramelized bananas followed by the remaining whipped cream and warmed cookie butter.
Pour ice-cream mix in 8" pan and freeze for 6-12 hours.