Cut 3 parchment pieces 12 x 18 inches. Set aside.
In a large mixing bowl, add the marshmallows. Set aside.
10 ounces mini marshmallows
In a saucepan, combine the chocolate chips and butter. Cook over medium heat, stirring frequently, until the mixture melts into a thick, smooth chocolate sauce.
1 ½ cups semi-sweet chocolate chips, ½ cup salted butter
Set aside for 5-8 minutes to cool off.
Pour the chocolate sauce over the marshmallows and stir until every piece is evenly coated.
Lay one sheet of parchment paper on a flat surface. Sprinkle a line of shredded coconut, about 8 inches long, down the center - this will form the base of your cookie log.
1 ½ cups shredded coconut
Spoon one - third of the marshmallow mixture on top of the coconut. Using the parchment paper, shape it into a log.
Sprinkle additional coconut over the top, then roll the log tightly in the parchment.
Refrigerate for at least 3 hours, or overnight, until firm.
Repeat the process with the remaining two parchment sheets and the marshmallow mixture.
Cut into ½ inch slices and serve.