1️⃣ Preheat the Oven
Preheat your oven to 350°F (175°C). Line baking sheets with parchment paper or silicone baking mats to prevent sticking.

2️⃣ Cream the Butter and Sugars
In a large mixing bowl, beat the softened butter, granulated sugar, and brown sugar together until light and fluffy (about 2-3 minutes).

3️⃣ Add Eggs and Vanilla
Mix in the eggs one at a time, followed by the vanilla extract, beating until fully incorporated.

4️⃣ Combine Dry Ingredients
In a separate bowl, whisk together the flour, cocoa powder, baking soda, and salt. Gradually add the dry ingredients to the wet ingredients, mixing on low speed until just combined.

5️⃣ Add Chocolate Chips and Marshmallows
Gently fold in the semi-sweet chocolate chips and mini marshmallows until evenly distributed.

6️⃣ Scoop the Dough
Using a cookie scoop or tablespoon, drop dough onto the prepared baking sheets, spacing them about 2 inches apart.

7️⃣ Bake the Cookies
Bake for 8-10 minutes, or until the edges are set but the centers are still soft.

8️⃣ Add Extra Marshmallows (Optional)
If desired, press a few extra mini marshmallows onto the tops of the cookies immediately after removing them from the oven for an extra gooey look.

9️⃣ Cool and Serve
Let the cookies cool on the baking sheets for 5 minutes before transferring them to a wire rack to cool completely. Serve as-is or with a dusting of cocoa powder or grated chocolate.