Preheat oven to 300 degrees F (this is not a typo, I bake at low heat so each layer bakes flat on top.)
Grease 4- 7inch cake pans, line bottom with parchment, grease parchment and flour pans.
In medium bowl combine the egg whites, 1/4 cup milk and vanilla.
In large bowl of mixer add the dry ingredients (flour, sugar, baking powder, salt).
Mix the dry ingredients for 30 seconds to combine.
Add the butter and the remaining 3/4 cups milk, mixing on low until ingredients are moistened.
With mixer on medium speed beat for 1.5 minutes to form the cake batters structure.
Scrape down the sides.
Slowly add the egg mixture in 3 batches, mix 20 seconds after each addition.
Scrape down the sides with spatula.
With mixer on medium slowly add the melted chocolate and mix until well combined.
Pour batter into cake pans evenly.
Bake 35-40 minutes (rotating cake pans half way through baking) or until light golden brown and toothpick inserted comes out clean.
Let cool completely.
In large sauce pan add the egg whites and sugar.
On medium heat you are going to whisk egg mixture until sugar is completely dissolved (you can test it by rubbing a small amount between your fingers to test it, it should be completely smooth).
Transfer to mixing bowl and with whisk attachment whisk on high until stiff peaks form and mixture is completely cooled.
Switch to paddle attachment.
On low speed add the butter one piece at a time. Mix until well combined.
With mixer on med/high speed slowly add in the melted white chocolate. Continue mixing until well combined, smooth and creamy.
Add in the food coloring (as much needed to reach desired shade) and mix until completely combined.
Put a small dollop of frosting on cake board/cake plate so the cake sticks.
Put on the first layer, pipe buttercream on top. Smooth with offset spatula.
Repeat with next two cake layers.
Place last layer of cake on top.
Crumb coat entire cake, refrigerate.
Apply and smooth out final coat of buttercream on top and sides. Pipe on bottom border.
Then pipe on decorative top. (All piping for this cake was done with wilton tip #32)*
Decorate with sixlets.