Preheat the oven to 350 degrees F and 2 cupcake pans with paper liners.
In a large mixing bowl, add the 1 ½ cups all-purpose flour, ¾ cup granulated sugar, ½ cup unsweetened cocoa powder, 1 teaspoon baking soda, and ½ teaspoon salt. Whisk until combined and set aside.
In a separate large bowl, add together the 1 cup buttermilk, ½ cup vegetable oil, 2 large eggs and 1 teaspoon vanilla extract. Whisk until the eggs are well combined.
Add the dry ingredients into the wet ingredients and mix until just combined.
Stir in ½ cup semi-sweet chocolate chips until evenly distributed in the batter.
Fill each paper liner ½ full (about 3 tablespoons) with batter.
Bake for 15-17 minutes or until a toothpick inserted into the center of a cupcake comes out mostly clean, moist crumbs are good!
Remove from the oven and allow the cupcakes to cool completely.
Once completely cooled, use a piping tip or small knife, cut a small hole in the center of each cupcake but be sure not to cut through the bottom.
Graham Cracker Filling
Add the ⅔ cup graham cracker crumbs, melted 2 tablespoons butter, and ½ teaspoon vanilla extract in a medium bowl. Stir until moistened.
Gradually add the ¼ cup powdered sugar while mixing. Continue until well combined.
Add the 2-3 tablespoons milk, 1 tablespoon at a time, until the crumbs are fully moistened and the mixture is no longer crumbly. It should be pipeable.
Add the graham cracker filling to a piping bag fitted with a large round tip or plastic bag with the corner cut off.
Fill the hole in the center of each cupcake to the top with the graham cracker mixture.
Marshmallow Frosting
To a large mixing bowl, add the 1 cup butter, 2 cups marshmallow crème and 1 teaspoon vanilla extract (I used clear vanilla extract). Beat with a hand mixer on medium speed until smooth.
Gradually add in 4 cups powdered sugar and beat until well combined. If the frosting consistency is too thick, you can add 1 tablespoon of milk at a time to reach your desired piping consistency.
Using a disposable piping bag fitted with a large round tip (I used a Wilton 2A tip), pipe the marshmallow frosting onto the cupcakes and top with desired toppings. These cupcakes are topped with graham cracker crumbs and a piece of Hershey’s chocolate.
Store in an airtight container at room temperature for up to 5 days.
Notes
Storage: Place the cupcakes in an airtight container and store at room temperature for up to 5 days. Freezing: Place in a freezer-safe container and store in the freezer for up to 3 months. Thaw at room temperature for 1 to 2 hours.