S’mores Gift Cakes

For the cake: Adjust an oven rack to the middle position and preheat the oven to 350F [180C]. Grease three 6 by 2 in [15 by 5 cm] cake pans and line the bottoms with parchment paper.

In a medium bowl or liquid measuring cup, combine the sour cream, milk, oil, eggs, and vanilla.

In the bowl of a stand mixer fitted with a paddle, combine the flour, sugars, cocoa powder, and baking soda and powder, and salt.

With the mixer running on low speed, slowly add the milk mixture. Increase the speed to medium and beat until combined, 20 to 30 seconds. Slowly pour the hot coffee into the batter and mix until just combined. Using a spatula, give the batter a couple of turns to make sure it is fully mixed.

Divide the batter evenly between the prepared pans. Bake for 25 to 35 minutes, until a wooden skewer or toothpick comes out with the tiniest bit of crumb.

Transfer the cakes to a wire rack and let cool for 30 minutes. Turn the cakes out onto the rack, remove the parchment paper, and let cool completely. Once cool, the cakes can be frosted or wrapped in plastic wrap and refrigerated overnight.

For the marshmallow fluff: In a small bowl, combine the cold water and the gelatin.

In a medium, heavy-bottomed saucepan fitted with a candy thermometer, combine the corn syrup, sugar, room-temperature water, and salt. Bring to a boil over medium-high heat, until the temperature reaches 240 [120C]; this will take a few minutes. Immediately remove the saucepan from the heat, and whisk in the gelatin. Set aside while whisking the egg whites.

In the bowl of a stand mixer fitted with a whisk, whip the egg whites and cream of tartar on medium-high speed until soft peaks form, 2 to 3 minutes.

Turn the stand mixer to low speed, and carefully pour the hot sugar syrup along the side of the mixing bowl, being careful not to hit the whisk attachment as you pour (transferring the hot mixture to a liquid measuring cup with a pour spout might make this task easier). When all the syrup is in the bowl, turn up the speed to medium-high and continue whisking until the mixture has doubled in volume, is quite thick and glossy, and sides of the bowl have cooled, 8 to 10 minutes. Add the vanilla and mix until combined.

For the ganache: Place the chocolate in a small bowl. Heat the heavy cream in a small saucepan until it is simmering and just about to boil. Pour the cream over the chocolate, cover the bowl with plastic wrap, and let it sit for 5 minutes. Remove the plastic and whisk until completely smooth. Cool to room temperature. When the ganache is cool, whisk for 30 to 45 seconds, until the ganache thickens a little bit. Let the ganache cool for ten minutes.

For the toasted graham cracker crumbs: Adjust an oven rack to the middle of the oven. Preheat the oven to 325F [165C]. Line a baking sheet with parchment paper.

Whisk together the graham cracker crumbs and sugar in a medium bowl. Add the melted butter and mix with a spatula until evenly incorporated. Spread the mixture on the prepared pan and toast in the oven until golden brown, 5 to 6 minutes.

To Assemble: Fill a piping bag fit with a large round tip with the marshmallow fluff. Pipe a layer of marshmallow fluff over the top of each cake. Toast the marshmallow fluff with a kitchen torch. Chill the cakes in the fridge for 30 minutes while you make the ganache. Top the marshmallow fluff with the ganache, using an offset spatula to even the chocolate. Sprinkle the tops of the cake with the toasted graham cracker crumbs. Let the ganache set for 30 minutes. Wrap and give the cakes as gifts, or slice and serve.