01 - In a blender, combine mashed bananas, whole milk, heavy cream, sweetened condensed milk, granulated sugar, vanilla extract, and salt. Blend until completely smooth.
02 - Transfer the blended mixture into the Ninja Creami pint container. Seal and freeze upright for a minimum of 12 hours or overnight.
03 - In a small bowl, mix graham cracker crumbs with melted butter and brown sugar until the texture is similar to wet sand. Set aside.
04 - Place the frozen base into the Ninja Creami machine and process on the 'Ice Cream' setting one time.
05 - After initial processing, carve a 1-inch well in the center of the ice cream and add the prepared graham cracker mixture.
06 - Reinsert the pint and run the 'Mix-In' function until thoroughly combined.
07 - Scoop the ice cream into bowls and garnish with whipped cream and sliced bananas if desired. Serve immediately.