Step 1

Preheat the oven to 350 degrees Fahrenheit and line a 12-compartment cupcake tin with liners. Set aside.

Step 2

In a large bowl or the bowl of a stand mixer, cream the butter, sugar, and brown sugar on medium speed using the paddle attachment for 2 minutes until creamed. Add the eggs, one at a time, stirring on low until smooth. Add the vanilla and stir to combine. In a small bowl, combine the cake flour, graham cracker crumbs, baking powder, salt, and cinnamon. Add half of those dry ingredients to the butter bowl, stirring on low to combine. Scrape the sides of the bowl and add half of the milk, repeating with the remaining dry ingredients and milk once combined. Scarpe the sides of the bowl and fold in any unincorporated bits. Use a large cookie scoop to portion the batter between the 12 tins. Bake in the preheated oven for about 16 minutes or until a toothpick inserted comes out clean. Allow to cool completely.

Step 3

Place a small saucepan with an inch or two of water on the stove on low heat. Fold up a paper towel and dampen it with the vinegar. Wipe down the inside of a metal mixing bowl (or the bowl of your stand mixer) as well as the whisk attachment for your mixer. (This cleans your bowl of any residue that may prevent your egg whites from fluffing. Once cleaned, add the eggs whites, sugar, water, and cream of tartar to the bowl. Place over the pot of water to set up a double boiler, being sure that the bottom of the bowl isn’t touching the water. Begin whisking gently regularly until the sugar completely dissolves, about 4-5 minutes. You can test the mixture for dissolved sugar by carefully rubbing a small amount of the mixture between your fingers- it should be smooth. Place the bowl on the mixer and begin whipping on high speed until the mixture fluffs to stiff peaks, about 9-10 minutes. Put the marshmallow topping into a piping bag fitted with a large tip and pipe the mixture onto the cooled cupcakes as desired. Once done, put the cupcakes into the freezer to chill briefly, about 15 minutes, while you make your chocolate topping.

Step 4

Combine the chocolate chips and oil in a microwave safe medium-sized bowl. Heat gently in 30 second increments (to prevent the chocolate from seizing) until the chocolate is melted and smooth. Pour the mixture into a glass or small bowl that you can dunk the cupcakes into. Once the cupcakes have chilled for a few minutes, quickly and carefully invert each one into the melted chocolate, dusting the finished tops with extra graham cracker crumbs if desired. Pop in the freezer again briefly to set up the chocolate and then serve! Cupcakes are best eaten the day they are assembled.