Chocolate Buttercream Christmas Tree Cake

Emma and I made a Chocolate Buttercream cake for Mike's birthday. Mike is a fan of the classics - chocolate cake, chocolate chip cookies and brownies - so for his birthday, we thought a classic chocolate cake with homemade buttercream would be perfect. We've become fascinated by Culinary Dots cakes - I've never seen anything quite like them. She recently made a cake with a Christmas Tree in the center that Emma thought would be fun to try. I made the cake and frosted it with the buttercream (recipe below), and she made the Tree 100% by herself. She started with an ice cream cone as the base, then added green buttercream. While Culinary Dots makes vegan treats... we used a boxed cake mix and this wonderful Homemade Chocolate Buttercream. I made the cakes in these 8" cake pans. 8" x 3" Cake Pans, $8 Chocolate Buttercream 1 stick of butter, melted 1 1/2 cups of cocoa 1/2 cup of milk (plus more) 2 sticks of butter, softened 5-6 cups of powdered sugar (plus...