Preheat the oven to 350 degrees F. Prepare one quarter sheet pan with non-stick spray, parchment paper, and another coat of non-sick spray. Set aside.

In a medium size bowl, sift the cake flour and baking powder. Set aside.

In the bowl of a stand mixer, fitted with the paddle attachment, beat the butter, canola oil, salt and sugar on high until fluffy and smooth, about 5 minutes.

Add the egg whites, one at a time to the bowl and beat on medium until well incorporated.

Turn the mixer on low and add half of the flour mixture to the butter mixture until fully incorporated. Then add all of the sour cream and blend well, and lastly, add the remaining flour mixture and 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.

Pour the cake batter in the quarter sheet pan and bake about 23-25 minutes or until a toothpick inserted into the middle of the cake comes out clean or with just a few crumbs. Make sure not to over bake.

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

 Once cooled, put a piece of parchment or a silpat on the counter. Invert the cake onto it and peel off the parchment or silpat from the bottom of the cake. Use the cake ring to stamp out 2 circles from the cake. These two full circles will be your top 2 cake layers. The remaining cake “scraps” will come together to make the bottom layer of the cake.

You can see pictures from the Milk Bar website HERE

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.

Bake the graham cracker pieces for 1o minutes. Let cool completely before using in the cake. Store in an airtight container until ready to use.

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.

For the first layer, clean the cake ring and place it in the center of a sheet pan lined with clean parchment. Line the cake ring with one strip of acetate.

Place the cake scraps together inside the ring and use the back of your hand to tamp the scraps together into a flat even layer.

Use the back of a spoon to spread one-third of the chocolate ganache in an even layer over the cake. 

Sprinkle about 1/2 to 1 cup graham cracker crumbs evenly over the ganache. Use the back of your hand to anchor them in place.

Use a piping bag to pipe about 1 cup of the toasted marshmallow filling on the graham crackers. 

For the second layer, gently tuck the second strip of acetate between the cake ring and the top ¼ inch of the first strip of acetate, so that you have a clear ring of acetate 5 to 6 inches tall – high enough to support the height of the finished cake.

Set a cake round on top of the marshmallow filling, and repeat the process for layer 1 (if 1 of your 2 cake rounds is jankier than the other, use it here in the middle and save the prettier one for the top).

For the third layer, nestle the remaining cake round into the marshmallow filling, cover the top of the cake with the remaining ganache and graham crackers.

Transfer the sheet pan to the freezer and freeze for a minimum of 12 hours to set the cake and filling. The cake will keep in the freezer for up to 2 weeks.

At least 5 hours before you are ready to serve the cake, pull the sheet pan out of the freezer and, using your fingers and thumbs, pop the cake out of the cake ring. gently peel off the acetate, and transfer the cake to a platter or cake stand. Let it defrost in the fridge for a minimum of 4 hours (wrapped well in plastic, the cake can be refrigerated for up to 5 days).