65th birthday S'mores chocolate cake

 65th Birthday S'mores Chocolate Cake

from Ellen's kitchen, with thanks to NYT

Note: to truly make this work, you need a kitchen torch. Next time, I will try chocolate drizzle on top as the final garnish.  How can that be bad?  Also, this cake is never bad, but best the day it is made - the graham crackers are only crunchy the day of baking.

Ingredients:

• For the cake:

• 1/2 cup unsalted butter, melted, plus more for greasing pans
• 2 1/4 cups granulated sugar
• 2 cups all-purpose flour
• 1 1/4 cups Dutch-process cocoa powder, sifted if lumpy
• 1 1/2 tsp baking powder
• 1 1/2 tsp baking soda
• 1 1/2 tsp kosher salt
• 1 cup sour cream, room temperature
• 1/4 canola oil
• 4 eggs, room temperature
• 1 tbs vanilla extract
• 1 cup hot coffee (decaf for this household)
• For the graham crumbles:
• 9 graham crackers (1 sleeve), finely ground (with rolling pin in zip-top bag or in food processor) or Biscoff cookies would likely work
• 2 tbs granulated sugar
• pinch kosher salt
• 5 tbs unsalted butter, melted
• 1 tsp vanilla extract
• For the buttercream:
• 4 large egg whites
• 1 cup granulated sugar
• 1 1/2 cups unsalted butter, cut into tablespoon-size pieces and softened until pliable but still a bit firm
• 2 tsp vanilla extract
• pinch kosher salt

Set:

• rack in center of oven and preheat to 350.  Butter two 9" baking pans and line the bottoms with parchment paper, buttering that as well.

In the bowl:

• fitted with the paddle attachment, combine the granulated sugar, flour, cocoa powder, baking powder, baking soda and salt.  Whisk until well combined with no lumps.

In a separate medium bowl:

• whisk the sour cream, melted butter, oil, eggs, and vanilla.  Add the sour cream mixture to the flour mixture.  Mix on low until dry ingredients are moistened, then turn the mixer to medium-high and mix for 2 minutes, scraping the bottom and sides of the bowl halfway through, until the batter is well blended.  Add the coffee and gently fold in with silicone spatula.

Divide:

• batter evenly between the prepared pans and tap on counter a few times to release air bubbles.  Bake until puffed and a toothpick inserted comes out clean, 25-40 minutes.

Set:

• pans on a wire rack and let cakes cools for 20 minutes.  Run knife around edges and carefully turn cake out onto a rack to cool completely.  Discard parchment.

While:

• cakes cool, make the graham crumbles:  Line a sheet pan with parchment paper.  Combine the graham cracker crumbs, sugar, and salt in a medium bowl.  Add the melted butter and vanilla and mix until evenly combined.  Use hands to grab and squeeze handfuls of mixture firmly, then place on baking sheet.  Repeat until all crumbs have been scrunched together and placed on baking sheet.  Break up larger bits into smaller crumbles, about the size of a blueberry.  Bake the crumbles until golden, fragrant, and crisp, about 10 minutes.  Cool completely on the pan, then break up any larger crumbles, if needed.

Make the buttercream:

• In the metal bowl of a stand mixer, whisk egg whites and sugar.  Set the bowl over a medium pot of simmering water.  The water should be just below the bowl.  Whisk frequently until sugar has dissolved and mixture is 160 degrees, 3-5 minutes.
  

Return the bowl to stand mixer:

• and use the whisk attachment to beat the egg-white mixture until stiff glossy peaks form, about 5 minutes.  Remove the bowl from the mixer and tip the bowl on its side.  Using a silicone spatula, spread meringue in a layer, covering the inside of the bowl.  Carefully use a kitchen torch to toast the top of the meringue until it is a deep golden brown.  Stir the torched meringue into the bowl, spread inside the bowl, and torch again.  Repeat one more time, stirring a final time.  Let the meringue sit until at room temperature.  
  

Switch to a paddle attachment:

• and reduce speed to medium-low.  With the mixer running, add the butter, a few tablespoons at a time, mixing until the butter has been incorporated before adding more.  Mix until the buttercream is smooth and fluffy.  If the mixture splits at any point, turn the speed of the mixer up for a few seconds and it will come back together.  After all the butter has been incorporated, beat in vanilla and salt.  The butter cream will be a creamy color speckled with toasted meringue bits.  (If needed, chill the buttercream for up to 30 minutes to firm it up before frosting.)

To assemble:

• Trim the tops of the cakes flat if needed.  Stir the buttercream vigorously to remove large air bubbles.  Place on of cakes, top-side up, on serving platter, and spread about 1 1/2 cups buttercream on top.  sprinkle with graham crumbles until completely coated, then press them gently into the frosting.  Add a small dollop of frosting in middle of cake to keep layers together and top with second layer of cake, top-side down.  Spread thin layer of butter cream all over cake, leaving about 1 1/2 cups buttercream in bowl, and refrigerate cake until buttercream firm, about 20 minutes.  

Frost:

• the cake with remaining buttercream, then top with remaining graham cracker crumbles.  Serve immediately or keep covered at room temperature for 2 days (crumbles soften as they sit).