Preheat oven to 350F, grease two 8-inch cake pans and dust with cocoa powder. Line bottoms with parchment paper.
Place all dry ingredients into the bowl of an electric mixer fitted with a paddle attachment. Stir to combine.
In a medium bowl whisk all wet ingredients (pour hot water/coffee in slowly as not to cook the eggs).
Add wet ingredients to dry and mix on medium for 2-3 mins. Batter will be very thin.
Divide batter evenly in your prepared pans. I used a kitchen scale to ensure the batter is evenly distributed.
Bake for 40-45 mins or until a cake tester comes out mostly clean.
Cool 10 minutes in the pans then turn out onto a cooling rack to cool completely.
Chocolate Swiss Meringue Buttercream:
Place egg whites and sugar into the bowl of a stand mixer, whisk until combined.*
Place bowl over a double boiler on the stove and whisk constantly until the mixture is hot and no longer grainy to the touch (approx. 3mins). Or registers 160F on a candy thermometer.
Place bowl on your stand mixer and whisk on med-high until the meringue is stiff and cooled (the bowl is no longer warm to the touch (approx. 5-10mins)).
Switch to paddle attachment. Slowly add cubed butter and mix until smooth.**
Add cooled melted chocolate and whip until smooth.
Place a layer of cake on a cake stand or serving plate. Top with approx. 1 cup of buttercream and spread evenly. Place the second layer on top and do a thin crumb coat on the cake. Chill for 20mins.
Place 1 cup of frosting on top and spread evenly. Smooth the sides and flatten the top, then use a large offset spatula to do a swirl pattern on top.
Using a piping bag fitted with a 1M tip, pipe rows of frosting around the cake, starting at the bottom. Apply even pressure as you rotate your turntable. Continue working your way up the cake to the top, making sure the seams all align at the back.
Decorate the top with chocolate curls, pearls, and flakes if desired.
* Wipe your mixer bowl and whisk down with lemon juice or vinegar to make sure it is completely grease-free and make sure there is no trace of yolk in your whites or your meringue will not stiffen.** The buttercream may look like it's curdled at some point. Keep mixing until it is completely smooth. If it looks soupy, place it in the fridge for 20mins and rewhip.