Preheat your oven to 375°F (190°C) and line baking sheets with parchment paper.
In a large bowl, cream the softened butter, granulated sugar, and brown sugar until the mixture is light and fluffy.
Into the butter and sugar mixture, beat the eggs one at a time, then stir in the vanilla extract.
In a separate bowl, whisk together your dry ingredients, the flour, baking soda, and salt. Gradually add this dry mixture to the wet ingredients until well combined.
Fold in the chocolate chips until evenly distributed throughout the dough.
Place the prepared cookie dough in the refrigerator for at least 30 minutes to allow it to chill.
Take a rounded tablespoon of cookie dough, flatten it in your palm, place a marshmallow in the center, and encase the marshmallow with the dough, forming a ball. The marshmallow does not need to be completely wrapped inside the dough. Place on the lined baking sheet spacing them about 2 inches apart.
Bake for 9 to 11 minutes or until the edges are golden brown.
Allow the cookies to cool on the baking sheets for a few minutes before transferring them to wire racks to cool completely.