These chewy cookies taste like a cup of your favorite hot chocolate, topped with melting marshmallows! They're easy to make, and perfect for Christmas, holiday parties, and snacking.
Preheat the oven to 350°F and line two baking sheets with parchment paper.
In a stand mixer bowl or large mixing bowl with an electric mixer, cream the butter, brown sugar, and granulated sugar together until light and fluffy, about 2–3 minutes. Beat in the eggs one at a time, then mix in the vanilla.
In a separate bowl, whisk together the flour, cocoa powder, hot cocoa mix, baking soda, baking powder, and salt. Add the dry ingredients to the wet mixture in two additions, mixing just until combined. Stir in the milk to slightly loosen the dough, then fold in the chocolate chunks; the dough will be thick.
Scoop generous 2–3 tablespoon portions of dough onto the prepared baking sheets, spacing the cookies several inches apart.
Bake for 8 minutes, then remove the tray from the oven and gently press a few mini marshmallows into the center of each cookie. Return the cookies to the oven for an additional 2-3 minutes, or until the marshmallows are puffed and the edges of the cookies are set while the centers remain soft.
Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely. Makes about 2 dozen large cookies.
Notes
Storage Instructions: Once the cookies have cooled completely, store them in an airtight container at room temperature for 3–4 days. If you’re stacking them, place a piece of parchment or wax paper between layers to protect the marshmallows.Freezing Instructions: Arrange the cooled cookies in a single layer on a baking sheet and freeze until firm, then transfer them to a freezer-safe container or zip-top bag. Separate layers with parchment paper to keep them from sticking. Freeze for up to 2 months.To Thaw: For best results, thaw in the refrigerator overnight.To Warm: Place a cookie on a microwave safe place and heat in the microwave for 8–10 seconds to make the chocolate melty and the marshmallows soft again.