Prepare a baking tray with a silicone baking mat or parchment paper.
In a stand mixer or with a handheld mixer and the paddle attachment, cream together the butter and two sugars on medium speed. 2-3 minutes.
6 tbsp butter, 1/4 cup brown sugar, 1/2 cup white sugar
Add in egg and vanilla and continue creaming.
1 egg, 2 tsp vanilla
Add in flour and baking soda and continue mixing until a soft dough forms. Do not overmix!
1 cup flour, 1/2 tsp baking soda
Mix in chocolate chips until just combined.
1/2 cup chocolate chips
Roll out the cookie dough into 1 tbsp balls. Then take ½ of a large marshmallow place it on top. Add approximately 1 tbsp of additional cookie dough on top and seal the cookie completely, with no marshmallow showing.
6 regular-sized marshmallows
Place into the refrigerator to chill for 30 minutes.
Once chilled, bake at 350°F for 8-10 minutes. The cookies will look soft, this is because the marshmallow has melted into the cookie. Remove from the oven and allow to cool on your baking tray for 5-10 minutes! Moving them around immediately after baking will cause a sticky mess.
Enjoy!