Preheat your oven to 350°F (175°C). Grease a baking pan or line it with parchment paper.

In a mixing bowl, cream the softened butter, brown sugar, and granulated sugar until light and fluffy, about 3–4 minutes.

Beat in the eggs one at a time, then mix in the vanilla extract until fully incorporated.

In a separate bowl, whisk together the flour, baking soda, and a pinch of salt. Gradually add to the wet ingredients, mixing gently.

Fold in the chocolate chips and graham cracker crumbs until evenly distributed.

Pour the batter into the prepared pan and sprinkle mini marshmallows over the top.

Bake for 20–25 minutes until the top is golden brown and a toothpick inserted comes out clean.

Cool in the pan for 10–15 minutes, then transfer to a wire rack to cool completely before slicing.