CAKE:
Heat oven to 350 degree F.
Grease and flour 4 x 7 inch cake pans, line bottom with parchment. Set aside.
Combine sugar, flour, cocoa, baking powder, baking soda and salt in bowl of mixer.
Add in the eggs, milk, oil and vanilla, beat medium speed for 2 minutes. Scrape sides of bowl as needed.
With mixer on medium speed (reduce to low speed if too much splashing occurs) slowly stream in the boiling water. Continue to mix until completely combined. Scrape sides and bottom of bowl as needed. Batter will be watery.
Pour into prepared cake pans (only fill pans 1/2 way, this cake rises alot) and bake 30-35 minutes or until toothpick inserted comes out clean.
Let cool completely.
BUTTERCREAM:
In medium 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).
Remove from heat and let mixture cool. (If mixture is too warm it will melt your butter when the time comes).
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.
Increase mixer to medium/high speed and mix until buttercream forms.
Add in the vanilla and mint oreo crumbs, continue mixing until completely mixed in.
ASSEMBLY:
Cut any humps off each cake layer that may have formed in baking.
Place first cake layer on cake board, secure it in place with a dab of frosting underneath.
Spread even layer of butter cream on top of the cake layer, smooth with offset spatula.
Repeat with the next two cake layers.
Add the top cake layer and crumb coat the cake with buttercream.
Refrigerate at least 30 minutes.
Put final coating of buttercream on cake.
Pipe swirls on top and garnish with Mint Oreo Cookies, chocolate crunches and buttercream roses or however you want to decorate it.
Keep in cool place and bring to room temp before serving.