In a medium size bowl, whisk together the cake flour, salt and baking powder. Set aside.

Add the egg whites, one at a time to the bowl and beat on medium until well incorporated. Make sure to scrape down the sides of the bowl between additions.

Turn the mixer on low and add 1/3rd of the flour mixture to the butter mixture and mix for 20 seconds. Then add half of the sour cream and blend well. Repeat alternately adding the flour, sour cream and remaining flour. Mix until incorporated.

Add the vanilla bean paste and beat on low until incorporated, only about 10 to 20 seconds. Scrape down the sides of the bowl and mix on low for another 10 to 20 seconds.

Remove cake from the oven and let cool in the pan for 10 minutes before inverting onto cooling racks.

Once cooled, you can level the cake layers if needed and then wrap well in plastic wrap and freeze for at least an hour before you assemble the cake. Can be stored in the freezer wrapped once in plastic wrap for about a week. If you want to store the cake layers longer, wrap twice with plastic wrap and then again with foil.

Preheat the oven to 350 degrees. Line a baking sheet with parchment paper. Set aside.

Place the crackers in a gallon sized zip-lock bag and crush them into pieces using a rolling pin. Set aside.

Melt the butter and mix in the brown sugar. Stir until combined.

Pour the butter and brown sugar mixture over the graham cracker pieces in the zip-lock bag and shake to coat.

Line a baking sheet with parchment paper and spray with nonstick cooking spray. Place the marshmallows on the cookie sheet. Place on the middle rack of the oven, and broil the marshmallows until golden brown on top, about 30-60 seconds. Keep your eye on them!

Remove the pan from the oven and gently turn the marshmallows over and broil them again until they are golden brown on the other side.

In the bowl of a stand mixer fitted with the paddle attachment, combine the butter and powdered sugar and beat on low until blended. Add the vanilla and mix on medium speed for about three minutes

With the mixer on low speed, add the marshmallow cream and (cooled) toasted marshmallows, and mix for about one minute.

In a microwave safe container, heat the cream for about 30 to 60 seconds. Pour the cream over the chocolate chips and let sit for 5 minutes. Stir the cream and chocolate until smooth and silky.

In a stand mixer fitted with the paddle attachment, beat the butter on medium high speed until light and fluffy, about 2 minutes.

With the mixer on low speed, gradually add the powdered sugar, followed by the graham cracker. Make sure to scrape down the sides and bottom of the bowl.

Add the cinnamon, vanilla, salt and cream.

Turn the mixer to medium-high speed and beat the frosting for about 5 minutes.

Before frosting your cake, make sure to mix the frosting by hand to push out the air pockets.

Place the first cake layer, top-side up, on a cake board.

Pipe a rim of the graham cracker frosting around the edge of the cake.

Evenly spread about 1/2 cup of the marshmallow filling over the cake layer.

Cover with about 1/4 cup graham cracker crumble and pat into place.

Drizzle chocolate ganache over the graham crackers.

Repeat these steps until you get to the final cake layer, which you'll place top-side down on the last layer of filling.

Apply a thin layer of frosting around the entire cake and then freeze the cake for 10 to 15 minutes. This is the crumb coat. The crumb coat is done to lock in the crumbs of the cake so you don't get them in your final coat of frosting.

After the crumb coat is set, finish frosting your cake.

For the piping, I combined some of my leftover marshmallow filling with the leftover frosting.