Add the milk, cottage cheese, monk fruit sweetener, powdered peanut butter, vanilla bean paste, salt, and xanthan gum to a high-speed blender container.
Process on high until completely smooth with absolutely no residual cottage cheese curds remaining.
Pour the blended mixture directly into a Ninja Creami pint container, secure the lid, and place flat in the freezer for 16 to 24 hours.
Remove the frozen pint and run the outer plastic walls under warm running tap water for 60 seconds to temper the icy outer layer.
Place the pint into the outer bowl assembly, attach the lid, and run the machine on the Lite Ice Cream cycle.
Inspect the spin; if dry or crumbly, add a single tablespoon of milk to the center and run the Re-spin cycle.
Use a butter knife to create a clear vertical channel down the center of the ice cream and pack the marshmallow creme into it.
Re-lock the pint assembly into the machine and run the Mix-In cycle to fully swirl the marshmallow throughout.
