Grasshopper Cake
Author: 
Yield: One 8-inch cake
 
Ingredients
For the classic chocolate cake layers
  • ¾ cup dark unsweetened cocoa powder
  • 1¼ cups hot water
  • ⅔ cup sour cream
  • 2⅔ cups all-purpose flour
  • 2 teaspoons baking powder
  • 1 teaspoon baking soda
  • ½ teaspoon salt
  • ¾ cup (1½ sticks) unsalted butter, softened
  • ½ cup vegetable shortening
  • 1½ cups granulated sugar
  • 1 cup firmly packed dark brown sugar
  • 3 large eggs, at room temperature
  • 1 tablespoon pure vanilla extract
For the crème de menthe buttercream
  • 2¼ cups sugar
  • ½ cup all-purpose flour
  • 2¼ cups milk
  • ½ cup heavy cream
  • 4½ sticks unsalted butter, soft but cool, cut into small pieces
  • 2 tablespoons crème de menthe
  • 2¼ teaspoons peppermint extract
  • 16 chocolate wafer cookies, homemade or store bought (such as Nabisco or Newman’s Own), optional
For the mint chocolate ganache
  • 6 ounces dark chocolate (60 to 72% cacao), coarsely chopped
  • ½ cup heavy cream
  • 1 tablespoon crème de menthe
  • ½ teaspoon peppermint extract
Instructions
Make the classic chocolate cake layers
  1. Preheat the oven to 325 degrees F. Butter three 8-inch round cake pans, line the bottoms with parchment paper, and butter the parchment. Dust with flour, and knock out the excess flour.
  2. In a medium bowl, combine the cocoa powder, hot water, and sour cream and set aside to cool.
  3. Sift the flour, baking powder, baking soda, and salt together into a medium bowl and set aside.
  4. In the bowl of an electric mixer fitted with the paddle attachments, beat the butter and shortening on medium speed until light and fluffy and ribbonlike, about 5 minutes. Add the sugars and beat until light and fluffy, about 5 minutes. Add the eggs, one at a time, beating well after each addition, then add the vanilla and beat until incorporated. Scrape down the bowl and mix again for 30 seconds.
  5. Add the flour mixture, alternating with the cocoa mixture, in three additions, beginning and ending with the flour mixture.
  6. Divide the batter among the prepared pans and smooth the tops. Bake for 35 to 40 minutes, rotating the pans halfway through the baking time, until a toothpick inserted in the center of each cake comes out clean. Transfer the cakes to a wire rack and let cool for 20 minutes. Invert the cakes onto the rack, remove the pans, and let cool completely. Remove the parchment.
Make the crème de menthe buttercream
  1. In a medium heavy-bottomed saucepan, whisk the sugar and flour together. Add the milk and cream and cook over medium heat, whisking occasionally, until the mixture comes to a boil and has thickened, about 20 minutes.
  2. Transfer the mixture to the bowl of an electric mixer fitted with the paddle attachment. Beat on high speed until cool. Reduce the speed to low and add the butter; mix until thoroughly incorporated. Increase the speed to medium-high and beat until the frosting is light and fluffy.
  3. Add the crème de menthe and peppermint extract and mix until combined. If the frosting is too soft, put it in the refrigerator to chill slightly, then mix again until it is the proper consistency. If the frosting is too firm, set the bowl over a pot of simmering water, then mix again.
  4. If you’re using the cookies, use a pastry bag or a large spoon to spread 1 to 2 tablespoons of the buttercream onto the bottom of one cookie. Press the bottom of a second cookie down on top of the buttercream. Repeat to make 8 sandwich cookies. Put the cookies on a baking sheet and chill in the refrigerator while you make the ganache.
  5. Leave the remaining buttercream at room temperature while you make the ganache.
Make the mint chocolate ganache
  1. Put the chocolate in a medium heatproof bowl and set aside.
  2. In a small saucepan over medium heat, bring the cream just to a boil. Remove from the heat and pour the cream over the chocolate. Let the cream sit for 2 minutes, then, starting in the center of the bowl and working your way out to the edges, slowly stir the chocolate and cream mixture in a circle until the chocolate is completely melted and the mixture is smooth. Add the crème de menthe and peppermint extract and stir until combined. Whisk for another few minutes to cool the ganache slightly, then let the ganache come to room temperature, about 15 minutes, whisking occasionally.
Assemble the Cake
  1. Place one cake layer on a serving platter. Trim the top to create a flat surface. Use an offset spatula to spread about ¼ cup of the ganache on top of the layer. Put the cake in the refrigerator for 1 minute to let the ganache set. Spread about 1 ¼ cups of the buttercream on top of the ganache. Top with the next cake layer, trim and frost with ganache and buttercream, then add the third layer and trim. Crumb coat the cake (see page 22) and put the cake in the refrigerator for 15 minutes to firm up the frosting. Frost the sides and top with the remaining buttercream. Garnish the cake with the cookies, if desired, and refrigerate for about 15 minutes to firm up the finished cake.
Notes
How to store: This cake will keep beautifully in a cake saver at room temperature (cool and humidity free) for up to 3 days. If your room is not cool, place the cake in a cake saver and refrigerate for up to 3 days. Remove the cake from the refrigerator and let it sit at room temperature for at least 2 hours before serving.
Recipe by Baked Sunday Mornings at http://bakedsundaymornings.com/2018/04/12/in-the-oven-grasshopper-cake/