01 -
Stir the cocoa, flour, salt, and baking soda together.
02 -
Blend the butter and sugar until it’s airy. Takes around 3-4 minutes.
03 -
Drop in eggs one by one. Mix in the vanilla after.
04 -
Gently fold wet and dry mixtures till just blended.
05 -
Let dough chill for an hour. Roll into balls and swirl in marshmallow.
06 -
Bake at 350°F for around 10-12 minutes, or until the sides feel firm.