Preheat oven to 350°F/180°C and line two baking trays with parchment paper. Set aside.
Melt the butter over low heat. Then, in a large bowl, whisk in the butter with the chocolate chips until smooth and glossy.
1/2 cup unsalted butter, 1 cup dark chocolate chips
Add in the white sugar and whisk. It's okay if it's grainy!
3/4 cups white sugar
Whisk in eggs and vanilla. Whisk for 2-3 minutes.
2 eggs, 1 tbsp vanilla
Add in cocoa powder, all-purpose flour, hot chocolate mix, baking powder, and salt. Using a spatula, gently fold in until no dry streaks are showing.
2 tbsp hot chocolate mix, 3/4 cups all-purpose flour, 1 tbsp cocoa powder, 1/4 tsp salt, 1/2 tsp baking powder
Take marshmallow fluff and drop 4-5 tablespoon's of it into the cookie dough. Then take a butterknife and swirl it into the dough a few times. Don't overswirl, we want marshmallow fluff to show in the cookies!
1/3 cup marshmallow fluff
Using a 2 oz cookie scooper, scoop 6 cookies onto the baking tray, spaced 2-3 inches apart from one another.
Bake the cookies for 10-14 minutes. The edges will be slightly cracked, and the middle will still look fudgy.
Remove from the oven and allow to cool on the baking tray. The heat from the tray allows the cookies to continue to bake after they've been taken out of the oven.
If your cookies are uneven and not circular, grab a bowl and gently swirl the cookies around. You can also take a spoon and gently press the edges in.
Enjoy!