Preheat oven to 325 degrees F.
In a medium bowl, combine the flour, baking soda, and salt and set aside. Whisk until ingredients are well combined. In the bowl of a stand mixer with the paddle attachment, add the butter, sugar, brown sugar, and vanilla and cream together until light and fluffy—about 3-4 minutes.
Add eggs one at a time, mixing them in after each addition. You may need to stop and scrape the bottom and sides of the bowl to make sure you combine everything.
Add the flour mixture to the butter mixture and mix on low until just combined. Make sure to scrape the bottoms and sides of the bowl so there are no streaks of butter.
Reserve about 1/4 cup each of the chocolate chips, teddy grahams, and both kinds of mini marshmallows and set aside, then combine the rest in a large bowl. Fold into the cookie dough, stirring to combine.
Using a small ice cream scoop, or a spoon, scoop and roll dough into 1¼" balls. Line them up 2" apart on a baking sheet lined with parchment paper, then use the palm of your hand to press the balls down gently so the dough ball is about 1" thick.
Bake for 10-12 minutes, or until the edges begin to turn lightly golden brown. Once baked, remove from the oven and add the reserved marshmallows, teddy grahams and chocolate chips.
Let the cookies cool on the baking sheets for a couple minutes before moving them to a wire rack to cool completely. Enjoy!