Preheat oven to 350 degrees F. Grease three 6-inch (or two 8- or 9-inch) cake pans with the baking spray. Line bottoms of pans with parchment and grease parchment and insides of pans. Lightly dust insides of pans with some cocoa powder.

In a large mixing bowl or bowl of stand mixer, mix the flour, sugar, cocoa powder, baking powder, baking soda, salt and espresso powder. Add the milk, oil, eggs and vanilla. Mix until combined. On low speed, gradually and carefully mix in the boiling water.

Divide cake batter among pans and bake 25 to 30 minutes, until a toothpick inserted in center comes out clean. Cool cakes in pans on wire rack 10 minutes. With icing spatula or butter knife, loosen sides of cakes from pans. Remove cakes from pans and cool completely on wire rack.

For the frosting, in a large bowl, beat the butter and salt until smooth and creamy. Gradually beat in the confectioners' sugar until smooth, scraping down sides of bowl occasionally. Mix in the vanilla and peppermint extracts. Gradually beat in the milk, 1 tablespoon at a time, until desired consistency.

Arrange cake layers on cake plate using half of the frosting in between the layers. Spread remaining frosting on outside of cake. Sprinkle crushed candy canes on top and press into sides of cake.

Tip: Cake layers can be made and cooled up to a month ahead. Wrap each layer tightly in plastic wrap and place in gallon-size freezer bags. Defrost, wrapped, in refrigerator before frosting and serving.