1-First Step: Preheat and Prepare: Begin by preheating your oven to 350°F and lining a baking sheet with parchment paper for easy cleanup. This step ensures your cookies bake evenly and don’t stick, setting the stage for success.

2-Second Step: Cream the Butter and Sugar: In a large bowl, cream together 1/2 cup softened butter and 3/4 cup packed light brown sugar until it’s light and fluffy this usually takes about 2-3 minutes with a mixer. Then, beat in 1 large egg and 1 teaspoon vanilla extract until fully combined, which adds moisture and flavor to the dough.

3-Third Step: Add Dry Ingredients: Gradually mix in the dry ingredients: 1 1/4 cups all-purpose flour, 1 1/3 cups graham cracker crumbs, 1 teaspoon cornstarch, 3/4 teaspoon baking soda, 1/2 teaspoon salt, and 1/4 teaspoon baking powder. Stir until the dough forms, which should take just a minute or two, creating that signature graham cracker base.

4-Fourth Step: Shape and Bake: Portion the dough into balls, about 1 tablespoon each, and flatten them into disks on the prepared baking sheet. Bake for 8-10 minutes until they’re golden around the edges, then let them cool completely on a wire rack this cooling step is crucial for the cookies to set properly.

5-Fifth Step: Make the Frosting: While the cookies cool, toast 3 cups mini marshmallows under the broiler for 1-2 minutes until they’re golden and gooey. In another bowl, beat 1 1/2 cups slightly softened butter until smooth, then add a pinch of salt and the toasted marshmallows, mixing until combined. Beat in 1 teaspoon vanilla extract, and gradually add 4 cups powdered sugar and 1 tablespoon heavy cream on high speed for 3 minutes to create a fluffy frosting.

6-Sixth Step: Assemble the Cookies: Pipe or spread the frosting onto the flat side of half the cookies, then top with the remaining halves to form sandwiches. Chill the assembled cookies in the fridge for 30 minutes this helps them hold together for the next part.

7-Final Step: Add Chocolate and Serve: Melt 6 ounces finely chopped semi-sweet chocolate in the microwave in 30-second intervals, stirring between each, until smooth. Dip or drizzle the cookie halves in the chocolate and let them set on a cooling rack. Serve right away for the best gooey experience, or store as needed the total prep time is about 45 minutes, cooking 10 minutes, and chilling 30 minutes.