Ashley warned us it's a BIG cake so make sure you have a loved one standing by to help devour it.
2 cups all-purpose flour
2 cups sugar
3/4 cup cocoa
2 teaspoon baking powder
1 1/2 teaspoon baking soda
1 teaspoon salt
1 teaspoon espresso powder
1 cup buttermilk
1/2 cup vegetable oil
2 large eggs
2 teaspoon vanilla extract
2 cups unsalted room temperature butter
7 3/4 cups sifted confectioners sugar
2-3 tablespoons of milk
2–3 teaspoon peppermint extract
Green food colouring gel
1/4 cup heavy whipping cream
1/2 cup chocolate chips
1. Preheat the oven to 350°F. Prepare two 9-inch cake pans by buttering and lightly flouring. Set aside.
2. For the cake, add flour, sugar, cocoa, baking powder, baking soda, salt, and espresso powder into a large bowl and whisk thoroughly to combine.
3. Add buttermilk, vegetable oil, eggs and vanilla extract to the flour mixture and mix together on medium speed until well combined. Reduce speed and add boiling water to the cake batter until well combined (the batter will be runny, but that results in a moist cake!)
4. Distribute cake batter evenly between prepared cake pans. Bake for 30–35 minutes, until a toothpick inserted into the center of the chocolate cake comes out clean. Remove from the oven and allow to cool for about 10 minutes, then transfer cakes onto a cooling rack. Refrigerate cake layers until it’s time to assemble and frost the cake.
5. For the buttercream frosting, use an electric mixer to whip 2 cups of unsalted and room temperature butter until light and creamy, for about 3–5 minutes on medium/high speed. Once the butter is pale in colour, slowly add sifted confectioners sugar one cup at a time on medium speed. Let the sugar fully incorporate before adding additional sugar.
6. Mix in 2–3 teaspoons of peppermint extract and green food colouring gel into milk and slowly pour in while whipping on high speed for another 3–4 minutes until very light and creamy. Add additional food colouring and flavouring until desired colour and taste is reached. Set aside.
7. For the chocolate ganache, heat up heavy whipping cream in a microwave and then pour the hot mixture over chocolate chips. Mix until well combined and glossy.
8. Prepare this step shortly before assembling your cake so the ganache has time to cool (it shouldn't melt the buttercream or drip down the side of the cake). If it solidifies too much, just pop it back into the microwave.
9. To assemble, slice off the tops of the two cake layers using a large serrated knife. Apply a small amount of buttercream onto the surface that the cake is being built upon (this will anchor them in place). Plop a large dollop of buttercream onto the first layer and smooth out using an offset spatula. Repeat process for the second layer. Apply another dollop of buttercream on the top layer and smooth it out so it covers the top surface. Next, apply more buttercream to the sides of the cake and spread it out thinly creating a "crumb coat". Pop the cake into the fridge for about 30 minutes so the buttercream solidifies and traps the crumbs.
10. Afterward, apply generous amounts of buttercream to the top and sides of the cake spreading it evenly with an offset spatula. Use a bench scraper to smooth the sides of the cake and then feel free to use the offset spatula or a spoon to create interesting textures on the cake. Pop the cake back into the fridge for another 30 minutes.
11. Next, pour the warm chocolate ganache into a fine-tipped bottle and begin pouring it along the top edge of the cake, so the ganache drips down the sides (the cold temperature of the cake will help the ganache solidify). Then, pour the remaining ganache on the top of the cake, smoothing it out with an offset spatula.
12. Finally, put the remaining buttercream into a piping bag with a frosting tip and pipe designs along the circumference of the cake. In between each dollop, place a halved peppermint patty.
13. Enjoy! But first, take photos because this cake is so beautiful you'll want to brag to your friends and family, and share it on social media.