Mini Marshmallow Hot Chocolate Cookies

Chocolate Cookies:
1/2 cup unsalted butter, room temperature
1/2 cup granulated sugar
1/2 cup dark or light brown sugar
1 large egg, room temperature
1 teaspoon vanilla extract
1 cup all-purpose flour
1/2 cup + 2 Tablespoons unsweetened cocoa powder
1 teaspoon baking soda
1/8 teaspoon salt
2 Tablespoons milk
Marshmallow Buttercream Frosting:
1 cup unsalted butter, room temperature
1 cup marshmallow creme
3 cups powder “confectioners” sugar
3 teaspoons vanilla extract
2 Tablespoons heavy whipping cream
pinch of salt
2 cups mini marshmallows
1 1/2 cup chocolate “melts”
For the cookies: Using a handheld or stand mixer, cream the butter for about 20 seconds. Add the sugars with the mixer running. Cream it all together until light and fluffy. Beat in the egg and vanilla.
In a separate medium size bowl, mix the flour, cocoa powder, baking soda, and salt together. Slowly add to the wet ingredients with the mixer running. The dough will be VERY thick. Add in the milk. Chill for at least 2 hours, covered. Chilling is MANDATORY.
Preheat oven to 350F degrees. Line two large baking sheets with parchment paper or silicone baking mats. Set aside.
Take 2 Tablespoons of chilled dough and roll into a ball. *wet your hands to make it easier to roll the dough into balls. Bake for 12 minutes.
To make the marshmallow buttercream:
Using a handheld or stand mixer, cream the butter and marshmallow creme until light and fluffy. Add the powder sugar, one cup at a time, beating until combined. Add heavy whipping cream, pinch of salt and vanilla. If frosting is too thick, add a little more heavy cream.
Allow the cookies to cool on the cookie sheet for at least 5 minutes before transferring to a wire rack to cool completely.
Once the cookies are cooled, melt chocolate chips in the microwave for about 1 minute or until chocolate melts are smooth. Pipe on frosting, smooth over with a knife, top with 5 mini marshmallows and drizzle chocolate on top of cookie (see photos).