Line an 8 or 9-inch square baking dish with parchment paper. Add about half of your cookies to the bottom of the dish. Set aside.
In a large electric mixing bowl, add white chocolate chips and marshmallow cream. Set aside.
In a medium saucepan over medium high heat, add sugar, butter, heavy cream, and salt. Bring mixture to a boil while stirring constantly.
Once boiling (a good rolling boil), allow mixture to boil for 4 full minutes (while stirring). Remove from heat.
Pour hot sugar mixture over the white chocolate and marshmallow in the mixing bowl. Turn the mixer on and beat on low until smooth, about one minute.
Fold in the remaining cookies, marshmallows, and half of the sprinkles. Pour into prepared baking dish.
Add the remaining sprinkles on top of the fudge. Allow to set, about 3 hours.
Notes
Use clothespins or binder clips to hold the parchment paper in place.
No need to refrigerate fudge. Allow to set at room temperature. You can refrigerate to speed up the process, but allow it to come to room temperature before slicing.
Store fudge in airtight container at room temperature for up to one week, or store in refrigerator for up to 3 weeks.