Double Double Cake

I have a friend who LOVES box cake. To go with her non-traditional wedding, she had mentioned that all she would want is a yellow cake with chocolate frosting, But they were going to forego cake all together. So, at the non-traditional bridal shower...We played laser tag and went out for lunch and had this---->


CAKE  
1x Yellow Cake box mix; follow box directions
1x Devils Food Cake box mix; follow box directions
1/2 tsp Sesame Seeds

FROSTING
Chocolate Buttercream Frosting
6oz dark chocolate, 70% cocoa
1/3c heavy cream
1/4c butter, room temperature
2-3c confectioners sugar

White Chocolate Buttercream Frosting
6 oz white chocolate
1/3c heavy cream
1/4c butter, room temperature
2-3c confectioners sugar

Bake both cake mixes into 9" round cake pans. Sprinkle sesame seeds on top of one of the yellow cake mixes.

Melt chocolate in a double boiler, add cream and stir. Put ganache in a stand mixer, with paddle attachment, and butter. Add powdered sugar, set aside.

Melt white chocolate in a double boiler, add cream and stir.
Put ganache in a stand mixer, with paddle attachment, and butter. Add powdered sugar. Stir in green food coloring. put in a pastry bag and set aside.

Leave the sesame layer as is, this will be the top bun. Take the other cooled cake and cut in half. Alternate yellow cake and chocolate cake, Stacking each layer with chocolate Frosting on the bottom. When you get to the final chocolate cake, pipe out green frosting on top. Place 'bun' layer on top.