Preheat oven to 350 degrees.
In a large bowl, mix together butter, sugar, and brown sugar. Mix until everything is smooth and creamy.
1 stick Butter, 1/4 cup Sugar, 3/4 cup Brown Sugar packed
Add in one egg, vanilla extract, and peppermint extract. Mix together.
1 Egg, 1/4 teaspoon Vanilla, 1/4 teaspoon Peppermint Extract
Then, add in cocoa powder, flour, and baking powder. On a low speed, mix all the dry ingredients to the dough.
1/3 cup Cocoa Powder, 1/2 teaspoon Baking Powder, 1 cup Flour
Add in chopped sandwich cookies to the dough and stir together with a spatula, making sure to scrape the bottom of the bowl to get everything mixed together.
1/2 cup Chocolate Sandwich Cookies
Drop dollops of marshmallow spread into the cookie dough and gently swirl with a knife. You want large swoops of marshmallow throughout the cookie dough.
1/2 cup Marshmallow Spread
Use a medium cookie scoop to scoop out the cookie dough and place on a parchment-lined baking sheet.
Top with a little swirl of marshmallow and few more crushed cookie crumbles.
Bake for about 12-14 minutes, the centers will still be slightly gooey.
Let cool slightly, and enjoy!