I could have swarn I saved the recipe I used for these cakes but I can't seem to locate it. Since they weren't my favorite I won't worry too much about it. If you want to bake some exactly like this, sorry! Whatever you do, invest in high-quality cocoa powder. It is my next step into the baking frontier.
The buttercream was adapted from both experience and reviewing several recipes:
1 cup butter, softened
3 cups powdered sugar (give or take)
1/2 tsp. mint extract
1/2 tsp. vanilla extract
The trick with the buttercream was to spend some additional time whipping it. With my first couple attempts at buttercream frosting I didn't spend enough time on this step and it was obvious with the finished product. Whip, whip, whip and just when you think you cannot whip any longer- whip some more. You won't be sorry, people will oooh and ahhhh at the frosting and then you will be very happy:)
I added mint and chocolate morsels to the batter for an extra dose of flavor.