Preheat your oven to 350°F (175°C) and line a 9x13-inch baking pan with aluminum foil.

In a large mixing bowl, whisk together the flour, graham cracker crumbs, baking powder, and salt.

In a separate bowl, cream together the butter and brown sugar until light and fluffy. Add eggs one at a time, mixing until incorporated.

Gradually add the flour mixture to the creamed mixture and mix on low speed until just combined.

Press half of the dough into the bottom of the prepared baking pan to form the crust.

Spread marshmallow topping evenly over the crust.

Sprinkle chocolate chips over the marshmallow layer.

Crumble the remaining dough over the chocolate chips.

Bake for 30-35 minutes until the top is golden brown and the edges are firm.

Cool on a wire rack, then refrigerate for a couple of hours before cutting into squares.