01 -
Preheat your oven to 350°F (175°C). Line a cupcake pan with 6 liners.
02 -
In a large bowl or stand mixer, cream together the softened butter and granulated sugar until light and fluffy.
03 -
Add the egg and vanilla extract, mixing well to combine.
04 -
In a separate bowl, whisk together the cinnamon, salt, baking powder, all-purpose flour, and graham cracker crumbs.
05 -
Gradually add the dry ingredients to the butter-sugar mixture, alternating with the milk, beginning and ending with the dry ingredients. Mix until just combined.
06 -
Divide the batter evenly among the cupcake liners, filling each about two-thirds full. Bake for 18-20 minutes, or until a toothpick inserted into the center comes out clean. Let the cupcakes cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.
07 -
In a heatproof bowl over a saucepan of simmering water, whisk together the egg white, granulated sugar, and cream of tartar until the sugar dissolves and the mixture is warm to the touch. Remove from heat and, using a hand mixer or stand mixer, beat the mixture until stiff peaks form. Add the vanilla extract in the last 30 seconds of mixing. Transfer the marshmallow filling to a piping bag fitted with a round tip.
08 -
Once the cupcakes have cooled, use a sharp knife to hollow out the centers, being careful not to cut through the bottom.
09 -
Fill each cupcake with the prepared marshmallow filling.
10 -
In a large bowl or stand mixer, cream the softened butter until smooth. Sift together the powdered sugar and cocoa powder to remove any lumps. Gradually add the powdered sugar and cocoa powder mixture to the butter, mixing on low speed until combined. Add the vanilla extract and enough milk to achieve your desired piping or spreading consistency.
11 -
Frost each filled cupcake with the chocolate buttercream frosting. Optional: Garnish with additional graham cracker crumbs or mini marshmallows for an extra s’mores touch.