Preheat oven to 350.
Link 3 9" cake pans with parchment paper and spray pan with non-stick cooking spray, set aside.
In bowl beat together your butter and sugar until fluffy.
Add your egg whites and vanilla and continue beating until combined, about 1 minute (do not over mix, you do not want to beat your egg whites into peaks).
In another bowl, combine your flour, baking powder and whisk together.
In alternate additions add your 1/3 flour mixture and your milk to the butter/sugar mixing after each addition.
Add in enough food coloring and mix on low until you get your desired color.
Divide your batter equally between your prepared pans.
Bake for about 30 minutes or until center is set and toothpick inserted comes out clean.
Remove from oven and allow to cool in pans for about 5 minutes before transferring to cooling racks.
Meanwhile to make your buttercream in large bowl mix together your butter and shortening until light and fluffy .
Add in your vanilla and mix to incorporate.
Adding 1 cup at a time, add your powdered sugar until you reach your desired consistency.
Lastly stir in enough food coloring to get your desired color.
Once cakes are cool add your bottom layer of cake to a turn table and top with about 3/4 cup of your buttercream and smooth to edges. Repeat with remaining layers.
Spread a thin layer of frosting over top and sides of cake to seal in the crumbs, place cake in freezer for about 15-30 minutes.
Once chilled pipe remaining frosting onto sides with a long flat ribbon tip and smooth out over sides and top of cake. Place back into freezer.
Meanwhile to make your ganache, place your chocolate in a heat proof bowl.
On stove top add your heavy cream to pan and heat until it just beings to boil, then remove and pour over your chocolate. Cover for about 5 minutes.
Remove top and stir your cream and chocolate together until its all melted and blended. Place in refrigerator until thickened slightly 15-20 minutes.
Remove cake from refrigerator and spoon a little of your ganache over the edges of your cake so it drips down the sides, add your candy pearls to your shorter drips if desired.
Using an open star tip, pipe swirls on top of cake and around bottom with your remaining buttercream.
Sprinkle top of cake with pink glitter sprinkles and add more of your pearls to the top swirls if desired.
Refrigerate until ready to serve.