In a large microwave-safe bowl, melt the semi-sweet chocolate chips, butter, and salt for 1 minute in the microwave. Stir well until it's smooth and completely melted.
1⅓ cups semi-sweet chocolate chips, 4 tablespoons salted butter, ½ teaspoon sea salt
Stir in the marshmallow cream until thoroughly combined. The mixture will be somewhat thick and foamy which is ok.
1 jar (7 oz) marshmallow cream
Add in the rice Chex cereal and stir until the cereal is completely coated.
9 cups Rice Chex Cereal
In a separate bowl, whisk together the powdered sugar and hot chocolate mix.
3½ cups powdered sugar, 2 packets hot chocolate mix
Layer the ingredients Inside a gallon-sized Ziplock bag. Place 1/3 of the powdered sugar mixture and then 1/2 of the Chex cereal mixture. Then add in another 1/3 of the powdered sugar mixture and the remaining half of the Chex cereal mixture. Finish off with the remaining powdered sugar mixture on top.
Securely seal the bag and gently toss everything together until all the Chex cereal is coated in powdered sugar. Gently massage the bag and move it side to side, up and down, to coat the cereal well.
Spread the muddy buddies onto a piece of parchment paper or wax paper on the countertop (or on a cookie sheet). Allow it to cool and set, at room temperature, for at least 30 minutes to 1 hour.
Once set, transfer the hot chocolate muddy buddies to a serving bowl and garnish with the mini semi-sweet chocolate chips and mini marshmallows. You can leave them as a garnish or mix them into the muddy buddies for serving.
2 cups mini marshmallows, 1 cup mini semi-sweet chocolate chips