Place egg whites and sugar into the bowl of a stand mixer, whisk till mixed.**
Place bowl over a double boiler on the range and whisk always till the combination is sizzling and now not grainy to the contact (approx. 3mins). Or registers 160F on a sweet thermometer.
Place bowl in your stand mixer and whisk on med-high till the meringue is stiff and cooled (the bowl is now not heat to the contact (approx. 5-10mins)).
Change to paddle attachment. Slowly add cubed butter and blend till clean.***
Add cooled melted chocolate and whip till clean.
Meeting:
Place a layer of cake on a cake board or plate. High with approx. 1 cup of buttercream and unfold evenly. Place second layer on prime and do a skinny crumb coat on the cake. Chill for 20mins.
Place 1 cup of frosting on prime and unfold evenly. Clean the edges and flatten the highest, then use a big offset spatula to do a swirl sample on prime.
Utilizing a piping bag fitted with a 1M tip, pipe rows of frosting across the cake, beginning on the backside. Apply even strain as you rotate your turntable. Proceed working your means up the cake to the highest, ensuring the seams all align on the again.
Enhance the highest with chocolate curls, pearls, and flakes if desired.