Ingredients
Method
Start by making the blackberry compote
- In a small bowl, whisk together the water and cornstarch. Set aside.
- In a medium saucepan, combine the blackberries, sugar, lemon juice, and cornstarch mixture over medium heat. Stir constantly, and try to break up the blackberries with a wooden spoon as you stir. Let the mixture cook fr 5-7 minutes or until thick and saucy, stirring almost constantly. Remove from the heat and stir in the vanilla extract. Allow to cool while we make the rest of the cake.
Make the simple syrup and sugared berries
- Melt together ½ cup of sugar and ½ cup of water in a small saucepan over medium heat, stirring occasionally, until sugar is dissolved. Add ½ cup fresh blackberries (not the frozen ones yet!) Let the berries sit in the syrup for about a minute, stirring. Then remove just the berries (keep the syrup in the pot) and toss them in the remaining ½ cup granulated sugar. Let the sugared berries sit at room temperature until ready to use on the cake.
- Add the ½ cup frozen blackberries to the syrup and stir. Allow to simmer for 5 minutes on low heat, covered. Then remove from the heat and let sit until ready to use later. (keep the berries in for now, we'll use them for the frosting later!)
Make the cake
- Grease three 8 inch round cake pans with butter and line the bottoms with parchment paper, then grease the paper. Set aside. Preheat the oven to 350℉.
- In a large bowl, whisk together the flour, cocoa powder, sugar, baking soda, baking powder, and salt. Set aside.
- In a medium bowl, whisk together the vegetable oil, eggs, sour cream, vanilla, and buttermilk until smooth and combined. Pour into the dry ingredients and then add the hot coffee. Whisk until smooth and combined. Whisk in the melted chocolate.
- Pour the batter evenly among the three cake pans. Bake for 25-27 minutes or until cake is pulling away from the sides of the pan and bounces back after being lightly tapped. Allow to cool completely in the pans set on a wire rack.
Make the frosting
- Remove the blackberries from the syrup (save the syrup to brush the cakes with!) . Add them to a small food processor along with another ½ cup of fresh blackberries. Pulse until completely broken up. Set aside.
- In a large bowl using a hand or stand mixer fitted with a whisk attachment, whip together the butter and shortening until smooth. Add the blackberry mixture, confectioners sugar, blackberry jam, vanilla extract, salt, and food coloring if using. Beat on low speed for 30 seconds, then turn up to high speed and whip for at least a minute.
Assemble
- At this point you should have cooled blackberry filling, blackberry syrup, three cakes, frosting, and sugared blackberries. Remove the cooled cakes from the pans and peel off the parchment paper. You may want to trim the tops of your cakes to give you a flat work surface. I use a serrated knife to do this
- Place one cake layer on a cake stand. Brush with the blackberry syrup. Spread a thin layer of frosting on top. Then, using a large circular piping tip, pipe a ring of frosting around the edge to act as a moat for the filling. Spread half of the cooled blackberry filling into the inside of the ring. Place the second cake layer on top and repeat this process, this time using all of the blackberry filling. Place the final cake layer on top and spread a very thin crumb coat of frosting over the top and sides of the cake. You should have about half of the frosting left, which you can place in the refrigerator for now. Place the cake in the freezer for about 15 minutes to set up.
- Once set, spread some of the remaining frosting over the sides of the cake to cover any cake that may be peeking out from under the crumb coat. Use a bench scraper or a spatula to smooth out the sides. Once completely covered, place the cake back in the freezer while we make the ganache. You should have around ½ to 1 cup of frosting left. Return it to the refrigerator.
Make the ganache
- Place the chopped chocolate in a liquid measuring cup. Set aside. Heat the heavy cream in a small saucepan over medium heat until simmering (not boiling!). Pour the hot cream over the chocolate and allow to sit for 3-5 minutes before stirring together. You should have a smooth and glossy ganache.
- Remove the cake from the freezer. Pour the ganache on top of the cake and use a spatula to push it towards the sides to drip down the cake. Don't pour all of the ganache at once, you may not want to use it all!
- Add the remaining frosting to a piping bag fitted with a large star piping tip. Pipe spirals on top of the ganache and along the sides of the cake. Top with sugared blackberries and crystalized ginger.
- Cake stays fresh covered in the refrigerator for up to 5 days!