Start by preheating your oven to 350 degrees F and grabbing all of your ingredients that you need for this recipe. Also grab your 8x8" parchment lined baking dish.
In an electric mixer, combine your butter and sugar and mix until combined on medium speed.
Once the butter and sugar have creamed together, add in the eggs and vanilla and mix until combined.
Next, sift your cocoa powder and hot chocolate mix in to the wet mixture on a low speed. Sifting this is helpful to avoid any clumps. Mix until thoroughly combined throughout the batter.
Next, add in your flour, salt, baking powder and mix well. Once mixed, fold in your chocolate chunks.
Transfer the batter to your lined baking dish and spread evenly with a spatula. Stick in the oven on the middle rack and bake for 25-28 minutes until a toothpick comes out of the brownies clean.
While the brownies are baking, make your frosting! Combine the butter, marshmallow fluff, and icing sugar in your electric mixer with the whisk attachment on medium speed until a frosting forms. I typically crush my candy canes finely by adding them to a blender.
Once your brownies have cooked and cooled, add the frosting and then sprinkle on your mini marshmallows and crushed candy canes. Slice in to 16 even squares and ENJOY!
