for the cake:

2 cups flour
2 cups sugar
3/4 cup unsweetened cocoa powder
2 teaspoons baking powder
1½ teaspoons baking soda
1 teaspoons salt
1 teaspoons espresso powder (I omitted this)
1 cup milk
½ cup vegetable oil
2 eggs
2 teaspoons vanilla extract
1 cup boiling water
for the frosting:

1¼ cups sugar (I always use superfine Baker's Sugar)
4 egg whites
1/4 teaspoon salt
1 teaspoon peppermint extract (double this is you want a really strong peppermint flavor)
1¼ cups unsalted butter (2¼ sticks), cut into slices and at room temperature
for the topping:

1/3 cup crushed peppermint bits
chocolate shavings (I just scrape a vegetable peeler over a semi-sweet chocolate bar)