01 - Combine mashed bananas, whole milk, heavy cream, sweetened condensed milk, granulated sugar, vanilla extract, and salt in a blender. Blend until fully smooth.
02 - Transfer the blended mixture to the Ninja Creami pint container. Secure the lid and freeze upright for a minimum of 12 hours or overnight.
03 - In a small mixing bowl, combine graham cracker crumbs, melted unsalted butter, and brown sugar. Stir until the texture resembles wet sand. Set aside.
04 - Once the ice cream base is fully frozen, insert the pint container into the Ninja Creami and process using the 'Ice Cream' setting.
05 - Create a 1-inch well in the center of the processed ice cream. Fill with the reserved graham cracker crumble.
06 - Reinsert the container and run the 'Mix-In' function until the swirl is fully incorporated.
07 - Scoop the finished ice cream into bowls. Serve immediately with whipped cream and sliced bananas as desired.