Preheat the Oven: Begin by preheating your oven to 350°F (175°C). Prepare a muffin tin by lining it with cupcake liners to prevent sticking.
Mix Dry Ingredients: In a large mixing bowl, combine the all-purpose flour, graham cracker crumbs, baking powder, baking soda, salt, cocoa powder, granulated sugar, and brown sugar. Whisk these ingredients together until they are thoroughly mixed and free of lumps.
Combine Wet Ingredients: In a separate bowl, crack the two large eggs and beat them lightly. Then, add the milk, vegetable oil, and vanilla extract to the eggs. Mix this mixture well until it is smooth and homogenous.
Combine Mixtures: Gradually pour the wet mixture into the dry ingredients, stirring gently with a spatula or wooden spoon until just combined. Be careful not to overmix. Once incorporated, gently fold in the mini chocolate chips, ensuring they are evenly distributed throughout the batter.
Fill Cupcake Liners: Using a spoon or an ice cream scoop, divide the cake batter evenly among the prepared cupcake liners. Fill each liner about two-thirds full to allow room for rising during baking.
Bake: Place the muffin tin in the preheated oven and bake for approximately 18-20 minutes. Check for doneness by inserting a toothpick in the center of a cupcake; it should come out clean or with a few moist crumbs attached.
Cool: Once baked, remove the cupcakes from the oven and let them cool in the pan for about 5 minutes. Afterward, transfer them to a wire rack to cool completely.
Make the Marshmallow Frosting: In a large mixing bowl, beat the softened butter using an electric mixer on medium speed until it becomes creamy and smooth. Gradually sift in the powdered sugar, mixing until fully combined. Add the mini marshmallows, milk, and vanilla extract to the frosting mixture, continuing to beat until it becomes fluffy and light in texture.
Frost the Cupcakes: Once the cupcakes are completely cool, generously spread the marshmallow frosting onto each cupcake using a spatula or a piping bag for a decorative finish.
Add Marshmallow Topping: Complete your cupcakes by placing half a marshmallow on top of each frosted cupcake. For an extra special touch, consider using a kitchen torch to lightly toast the marshmallow, giving it that nostalgic campfire flavor and a beautiful golden color.
Notes
For an extra special touch, consider using a kitchen torch to lightly toast the marshmallow topping.