Cupcakes:

Preheat the oven to 350°F. Line a cupcake pan with paper liners and set aside.

In a medium bowl, sift together the flour, cocoa powder, baking powder, baking soda, and salt. Set the dry ingredients aside while you prepare the batter.

In a separate large mixing bowl, add the butter, granulated sugar, and brown sugar. Using an electric mixer, beat on medium-high speed until the mixture is pale, creamy, and fluffy.

Add the eggs one at a time, mixing for about 30 seconds after each addition. Add the vanilla extract and mix until well combined.

Add half of the dry ingredients to the butter and sugar mixture along with ½ cup of the milk. Mix on low speed just until combined. Add the remaining dry ingredients and remaining ½ cup of milk, then continue mixing on low until the batter is smooth. Be careful not to overmix.

Divide the batter evenly between the cupcake liners, filling each about ⅔ full.

Bake for 15–18 minutes, rotating the pan halfway through baking for even results. The cupcakes are ready when a toothpick inserted into the center comes out clean or with just a few moist crumbs.

Allow the cupcakes to cool in the pan on a wire rack for about 25 minutes. Remove them from the pan and transfer them directly to the wire rack. Let them cool completely before frosting, about 1 hour.

Marshmallow Frosting:

Add the slightly softened butter, room-temperature marshmallow creme, and vanilla bean paste to a large mixing bowl. For the best consistency, the butter should still feel slightly cool and firm rather than completely soft. Leaving it at room temperature for about 30–60 minutes should do the trick.

Beat the butter, marshmallow creme, and vanilla bean paste together on medium speed for about 2 minutes, or until the mixture is smooth and creamy.

Scrape down the sides and bottom of the bowl with a rubber spatula to make sure everything is evenly incorporated.

Add the powdered sugar. Begin mixing on the lowest speed for about 30 seconds, or until the powdered sugar has mostly incorporated into the marshmallow mixture.

Stop the mixer and scrape down the bowl again. Increase the mixer to medium-high speed and beat for another 30–45 seconds, until the frosting is smooth, fluffy, and well combined.

Before frosting the cupcakes, refrigerate the marshmallow frosting for about 1 hour. Chilling allows the butter and marshmallow creme to firm up, making the frosting easier to pipe or spread.

If the frosting still seems too soft after chilling, mix in an additional ½ cup of powdered sugar. Alternatively, add 1 tablespoon of cornstarch and mix again until the frosting reaches your desired consistency.

Garnish:

Once the cupcakes are completely cool, frost each cupcake generously with the marshmallow frosting.

Finish each cupcake with a piece of graham cracker, a piece of Hershey’s chocolate bar, and a few mini marshmallows for that classic s’mores-inspired finish. Serve and enjoy!