Preheat your oven to 350°F (175°C) and grease a 9x13 inch baking pan.

In a large mixing bowl, cream together the softened butter, brown sugar, and granulated sugar using an electric mixer for 2-3 minutes.

Add eggs one at a time, mixing well, then add the vanilla extract and blend until well incorporated.

Whisk together the flour, baking soda, and salt in a separate bowl, then gradually add to the wet ingredients.

Fold in the graham cracker crumbs and chocolate chips gently using a spatula.

Spread half of the cookie dough into the prepared baking pan, pressing it down firmly.

Sprinkle mini marshmallows over the base layer, then dollop spoonfuls of the remaining dough over the marshmallows.

Scatter additional chocolate chips and marshmallows on top of the final layer.

Bake for 25-30 minutes until the edges are golden brown.

Cool in the pan for about 10 minutes, then transfer to a wire rack to cool completely and slice into squares.