In a medium saucepan, combine the strawberries, raspberries, blueberries, blackberries, sugar, and lemon juice. Place over medium heat and cook, stirring occasionally, until the fruit begins to release its juices and soften (about 10 minutes). If it’s sticking to the pan, lower the heat or add one or two tablespoons of water.

Once the syrup has been reduced, and the berries are falling apart, mix the cornstarch with the water in a small bowl.

Stir the cornstarch mixture to make sure it’s smooth, then pour it into the saucepan while stirring. Increase the heat slightly and bring the mixture to a gentle boil. Cook for 1–2 minutes, stirring constantly, until the jam thickens and looks glossy.

Place a fine-mesh sieve over a clean bowl. Carefully pour the hot jam through the sieve, using a spoon or spatula to press the liquid through while leaving seeds and skins behind. Discard the solids.

Cover the surface of the jam with plastic wrap.

Let it cool to room temperature. Refrigerate for at least 2 hours, and up to 2 weeks, or freeze for longer storage.

Start by pre-heating the oven to 350ºF. Grease and line with parchment as many 8-inch cake pans as you have. Grease the parchment and the sides of the pan as well. You will have to bake the batter in batches, unless you have 8 pans and the oven space.

Make sure to weigh the bowl you’ll be using before starting the recipe, this way you can easily do the math of how much batter goes in each pan. It’s very important to be precise, or you may run out of batter to have all eight layers. It’s highly recommended that you use a scale for this recipe.

In a large mixing bowl, mix the flour, sugar, cocoa powder, baking powder, baking soda, salt, and espresso powder (if using). Whisk to combine.

In another bowl, combine the eggs, vegetable oil, buttermilk, sour cream, and the vanilla extract. Whisk until completely incorporated.

Pour the wet ingredients over the dry ingredients and whisk until combined. When the batter is incorporated, add the hot coffee and mix to combine.

Whisk until the batter is smooth. The chocolate cake batter will be very thin and liquidy.

I like to transfer it to a bowl with a spout to help distribute the cake batter between the cake pans, which helps with such a runny batter.

Divide the batter evenly between the cake pans.

Tap them gently against the counter to release any bubbles.

Bake the cakes in the oven for about 15 minutes, until a toothpick inserted into the cake comes off clean.

Let the cakes cool down for 10 minutes in the pan. Flip it over onto a greased parchment lined tray, because the cake will be very thin, delicate, and moist, so it can stick to the tray and you won’t be able to lift it. Make sure the parchment is greased or it will stick to the cake.

Proceed to baking the next batch.

Then remove the cakes from the pan. Let them cool down. If you aren’t frosting the cake on the same day, I recommend you wrap each layer individually in plastic wrap and then freeze until you are ready to use the cake layers. When you are ready to frost the cake, you can simply use the frozen cake layers, or let them sit on the counter for 20 minutes before frosting the cake.

Place the chocolate chips or chopped chocolate in a bowl. Place in the microwave for 15 to 30 second intervals, stirring until melted.

Heat up the heavy cream gently, until just hot, and pour over the melted chocolate chips.

Let the mixture cool down for about 15 minutes.

Sift the powdered sugar and cocoa powder together.

In a large bowl, or the bowl of a stand mixer, beat the butter for 1 minute using the paddle attachment, until creamy.

Add the sifted powdered sugar and cocoa powder slowly, while beating the butter on low, scraping the bowl every so often to ensure everything is getting nicely incorporated together.

Add the melted and cooled chocolate and heavy cream mixture along with the vanilla to the bowl, and beat on low until combined.

Add the vanilla extract and mix.

To assemble the cake, start by placing one cake layer on a cake plate.

Spread a very thin later of buttercream on top. Then pipe a thin circle of frosting around the edges of the cake.

Fill the center with a few tablespoons of the strained and cooled jam, spreading on an even layer, without over filling.

Top with another cake layer. Repeat until you reach the top of the cake.

If the cake is sliding, consider placing it in the fridge or freezer for ten to twenty minutes before continuing assembly.

Always remember to keep the frosting covered.

Spread the frosting on top of the cake and all over the sides of the cake.

Use an offset spatula to smooth out the top of the cake.

And use a bench scraper to smooth out the sides of the cake.

You can place the cake in the fridge for 20 minutes after applying this first layer of frosting, this will seal all the crumbs in and give you a clean smooth finish once you apply a thicker layer of frosting.

Remove the cake from the fridge and spread a thick layer of frosting all over the sides and top of the cake. Repeat the smoothing process with the spatula and cake scraper.

Place the cake in the fridge for at least one hour before doing the ganache drip.

In a small saucepan or microwave-safe bowl, heat the cream until just starting to simmer (do not boil).

Place the chocolate in a heatproof bowl and pour the hot cream over it. Let sit for 1 minute to soften.

Stir from the center outward until glossy and fully combined.

Let sit at room temperature until slightly thickened but still pourable (about 15–20 minutes). It can take longer depending on how hot the cream was.

Test the consistency of the ganache on the side of a chilled bowl or plate. If it slowly drips down without running off completely, it’s ready. You can also carefully test on the side of the cake.

You can either use a spoon to drip, or a piping bag.

Start dripping the ganache down the sides of the cake by piping or spooning it in drops around the edges of the cake. Once you go around the whole circumference, spread the remaining ganache in the center.

Let the ganache set for at least ten minutes in the fridge, until set but not fully dry. Decorate with berries if desired, and chocolate shavings.

Store the cake in the fridge for up to 4 days, in an air tight container. You can also wrap the cake in plastic and freeze it, for up to 2 months.