Preheat oven to 350 degrees. Grease two 8-inch round baking pans and dust with cocoa powder. Line bottoms with parchment paper.
Place all dry ingredients in the bowl of an electric mixer fitted with the paddle attachment. Stir until combined.
In a medium bowl, whisk together all of the wet ingredients (slowly pour in the hot water so the eggs don’t cook).
Add the wet ingredients to the dry ingredients and mix on medium speed for 2-3 minutes. The batter will be very fluffy.
Pour the batter evenly into the prepared pans. I used a kitchen scale to make sure the batter was evenly distributed.
Bake for 45 minutes or until a cake tester comes out mostly clean.
Leave the pans to cool for 10 minutes in the pans, then invert onto a wire rack to cool completely.
Chocolate Buttercream Swiss Meringue:
Place the egg whites and sugar in the bowl of an electric mixer and beat until combined.
Place the bowl over a double boiler on the stove and beat constantly until the batter is hot and no longer grainy to the touch (about 3 minutes).
Or register 160°F on a candy thermometer.
Place the bowl of an electric mixer on medium-high speed and beat until the meringue is stiff and cool (the bowl is no longer warm to the touch (about 5-10 minutes)).
Switch to the paddle attachment. Slowly add the butter cubes and beat until smooth.
Add the cooled melted chocolate and beat until smooth.
Assemble:
Place one cake layer on a cake board or plate. Cover with about a cup of buttercream and spread evenly. Place the second layer on top and cover the cake with a thin layer of crumbs. Refrigerate for 20 minutes.
Place about a cup of frosting on top and spread evenly. Smooth the sides and flatten the top, then use a large spatula to create a spiral pattern on the top.
Using a piping bag fitted with a 1M tip, pipe the frosting around the cake, starting at the bottom.
Apply even pressure while rotating the turntable. Continue working your way up the cake to the top, making sure to line up all the seams at the back. Decorate the top with chocolate curls, pearls, and flakes if desired.