Ingredients
Cooking spray, for pan
1 1/4 c. butter, softened
1 c. lightly packed brown sugar
1 c. granulated sugar
4 large eggs
2 tsp. pure vanilla extract
2 c. all-purpose flour
1 c. graham cracker crumbs
2 tsp. baking powder
1 tsp. kosher salt
1 c. buttermilk
1 1/2 c. butter, softened
1 c. unsweetened cocoa powder
2 tsp. pure vanilla extract
Pinch kosher salt
3 3/4 c. powdered sugar
1/3 c. to 1/2 c. heavy cream
3 c. marshmallow crème
1/4 c. graham cracker crumbs
Preparation
Step 1Make cakes: Preheat oven to 350°. Line three 8” cake pans with parchment paper and grease with cooking spray. In a large bowl using a hand mixer (or in the bowl of a stand mixer) beat together butter and sugars until light and fluffy. Add eggs one at a time, beating well after each addition. Add vanilla and mix until combined. Step 2In another large bowl, whisk together flour, graham cracker crumbs, baking powder, and salt. Add half the dry ingredients to the wet ingredients and beat until just combined. Pour in buttermilk and beat until fully incorporated. Add remaining dry ingredients and mix on low until just combined. Step 3
Divide batter between cake pans and bake until slightly golden on top and a toothpick inserted into the middle of each cake comes out clean, about 30 minutes. Let cakes cool in pans for 10 minutes, then invert each onto a cooling rack to cool completely. Step 4
Make frosting: In a large bowl using a hand mixer, beat butter, cocoa powder, vanilla, and salt until creamy. Gradually add powdered sugar and beat until combined. (The texture will be crumbly!) Gradually add heavy cream until the frosting is smooth.Step 5Assemble cake: Dab a small bit of frosting onto your cake plate or serving platter, then place the first layer of cake on top. Spread a thin layer of frosting on top. Microwave marshmallow crème for 20 seconds (to make it easier to spread!) then spread a thin layer of marshmallow crèmeover frosting, leaving a 1/2" border all around to prevent marshmallow crème from oozing out. Repeat layering process, then top with final cake layer. Cover entire cake with frosting, then spread marshmallow crème on top, spreading it all the way to the edges of the cake. (It will naturally drip down!) Step 6Use a kitchen torch to toast the drips along the cake and garnish top of cake with graham cracker crumbs.
