This recipe is broken down into four parts - the blackberry compote filling, the chocolate ganache filling, the chocolate cake, and the Blackberry Swiss meringue buttercream
Blackberry compote filling:
600 grams blackberries
200 grams jam sugar (sugar with Pectin)
200 grams granulated sugar
2 tablespoons fresh lemon juice
1 tablespoon cornstarch mixed with 1 tablespoon water. (Mix this up right before you’re about to use it)
Put the blackberries, both sugars and the lemon juice into a pot. Bring to a boil and let simmer for 15 min or until the temperature reaches 105-110c (220F).
Add the cornstarch slurry to the jam and quickly stir to combine (It’s important to do this quickly so that the cornstarch doesn’t clump up).
Set aside to cool and store in the refrigerator.
Chocolate ganache filling:
225 grams chocolate
230 ml heavy cream
Finely chop the chocolate and put it into a heatproof bowl.
In a separate heavy pot, heat the heavy cream just until it starts to boil.
Pour the heavy cream over the chocolate and let sit for 2 min.
Slowly stir until all of the Chocolate is melted and combined with the heavy cream. Set aside to harden up.
330 grams all purpose flour
350 grams granulated sugar
135 grams unsweetened cacao
2 1/2 teaspoons baking soda
1/2 teaspoon salt
170 ml neutral oil
220 ml water
50 ml coffee
1 teaspoon vanilla extract
275 ml full fat milk
3 large eggs
In a large bowl mix together the flour, sugar, cacao, baking soda and salt.
In another bowl mix together all of the wet ingredients.
Add about 2/3 of the wet ingredients into the dry. Mix until smooth.
Add the rest of the wet and mix until everything is combined.
Pour into 3 x 20 cm cake pans (greased with parchment paper in the bottom)
Bake for about 40-50 min until a skewer inserted into the middle of the cake comes out clean.
Let the cakes cool before you level them out.
Once the cakes are fully cooled down and leveled out you can start to assemble the cake.
Place one cake layer on top of the plate/cake stand you’re using.
Spread a thin layer of chocolate ganache all over. Make a thick border of chocolate ganache (about 2-3 cm thick and 1-2 cm high) just on the edge of the cake, all around (don’t fill in the middle).
Fill in the empty middle with blackberry jam.
Place the next layer on top and do the same exact thing finishing of with the third layer of the cake.
One the cake is filled and stacked, place it in the fridge while you make the Swiss meringue buttercream.
Blackberry Swiss meringue buttercream:
6 large egg whites
380 grams granulated sugar
340 grams unsalted butter
2-3 tablespoons blackberry syrup
Food coloring to make it purple (optional)
Add the egg whites and the sugar into a heatproof bowl.
Place over a pot of simmering water (the bowl should not touch the water)
Whisk constantly until the sugar is dissolved (temp should be 160F).
Transfer the mixture into a stand mixer fitted with a whisk attachment. Beat on medium-high speed until the bowl is at room temp and the meringue forms stiff and glossy peaks (about 20 min)
Once it’s done, slowly start adding the butter 1 tablespoon at a time, adding more after each tablespoon is absorbed into the mixture.
Mix until all of the butter is combined and beat the mixture until it reaches a thick glossy consistency.
Add the food coloring and the blackberry syrup and mix until combined (add more depending on your desired intensity of flavor)
Frost and decorate the cake and done!