1. For the cake, preheat the oven to 300 °F (150 °C). Grease three 8-inch (20 cm) round cake pans. Dust them with flour, tapping out any excess flour and then line the bottom of the pan with parchment paper.
2. Place the chopped chocolate in a small bowl, cover with the hot coffee and let set a minute. Whisk to melt the chocolate and set aside (don’t worry if the mixture doesn’t look smooth).
3. In a large mixing bowl, sift the sugar, flour, cocoa powder, baking soda, baking powder and salt. In a separate bowl, whisk the buttermilk, oil, egg, egg white and vanilla. Add the buttermilk mixture to the dry ingredients, stirring by hand until smooth. Add the melted chocolate liquid and whisk in. Divide the batter between the prepared pans (the batter will be fluid, and will not fill the pans, but the cake rises beautifully) and bake for about 30 minutes, until a skewer inserted in the centre of the cake comes out clean. Allow the cakes to cool on a rack for 30 minutes before removing them from the pans to cool completely.
Buttercream and Assembly
1. For the buttercream, place the egg whites with a pinch of salt in a large mixing bowl (and use electric beaters) or in the bowl of a stand mixer fitted with the whip attachment and whip on medium speed until the whites are foamy. While increasing the speed to high, slowly pour in 1/2 cup (100 g) of the sugar until the whites just begin to hold a soft peak.
2. Bring the remaining 1 ½ cups (300 g) of the sugar and the water to a full boil over high heat in a small saucepot. Using a candy thermometer to measure, boil the sugar without stirring until it reaches 240 °F (116 °). Immediately remove the pot from the heat. Turn the mixer (or beaters) on high speed and very carefully pour the sugar down the side of the bowl (never into the moving beaters, or it will splatter). Continue to mix the meringue on high speed until it has cooled to room temperature (this could take 8-10 minutes).
3. Still on high speed, starting adding the butter, a little at a time but there is no need to wait until the first bit is worked in before adding the next. Scrape down the bowl once or twice while beating, and don’t worry when the meringue deflates a little when you add the butter – it’s meant to happen. Beat in the vanilla.
4. Spoon about 1 ½ cups (375 mL) of the buttercream into a separate mixing bowl, and beat the melted chocolate into it, followed by the berries. Set the remaining buttercream aside to mask and decorate the cake. Work with both buttercreams while at room temperature.
5. To assemble the cake, place one of cakes on a cake board or plate and spread half of the chocolate-berry buttercream over the top. Place a second layer of cake on top, pressing slightly to secure it in place. Spread the remaining half of the chocolate-berry buttercream on this and top with the last cake.
6. This cake is frosted using 3 tones of pink, a light, a medium and a dark pink. Tint the whole batch of remaining buttercream with just a little pink for the light tone. Use this to frost the top and then the sides of the cake, spreading to level. Make sure the top is fully covered (masked) with the light pink buttercream, but the sides can have a sheer layer (crumb coat), since they will have additional buttercream piped on.
7. Place a THIRD of the remaining buttercream into a piping bag fitted with a large plain tip. Tint the remaining buttercream to a medium pink and spoon HALF of this into a piping bag fitted with a large plain tip. Now add more pink colouring to the rest of the buttercream to make a dark pink and all of this goes into a third piping bag fitted with a large plain tip. You should now have THREE piping bags of buttercream: 1 light pink, 1 medium pink, and 1 dark pink.
8. To create a petal pattern on the cake, Pipe a single row of dots vertically down the side of the cake, 2 of each colour, starting with the darkest at the bottom, moving to the lightest at the top (2 dark, 2 medium, 2 light). Use a small palette knife to “smear” each dot in the same direction, so that it looks like a petal (you may need to wipe off the spatula occasionally). Now pipe another row of dots overtop where the “petals” flatten, but moving the colours up one row (1 dark, 2 medium, 2 light, 1 dark). Repeat this pattern of moving the colours up one row and continue piping and smearing around the cake. When you reach where you started, make the smear a smaller, shorter move so it blends in.