Rocky Road Popcorn Fudge

Name: Rocky Road Popcorn Fudge
Prep time: 10 min
Cook time: 1 h 10 min
Total time: 1 h 20 min
Yield: 1
Cuisine: american
Ingredients: 12 ounces semisweet chocolate chips; 1 (14-ounce) can sweetened condensed milk; 2 tablespoons unsalted butter; 1 cup large marshmallows, cut into 4 squares; 2 cups popcorn, plus more for topping; Powdered sugar, to garnish