CHOCOLATE CAKE

1. Preheat the oven to 350°f / 180°c. Lightly spray a Texturra Performance Square Pan, 9x9 inch with baking spray and set aside.
2. In a large bowl, whisk together the flour, sugar, cocoa, espresso powder, salt, baking soda, and baking powder. Add the eggs, yolk, vanilla bean paste, oil, and milk, and mix to combine well. Add the boiling water and whisk until incorporated.
3. Transfer the batter into the prepared pan, and tap a few times on a flat surface to remove any excess bubbles.
4. Bake the cake for 30 to 35 minutes, until the centre springs back, or a cake tester inserted in the middle of the cake comes out cleanly.
5. Cool in the pan for 15 minutes, then transfer to a wire rack and allow to cool completely.

MIXED BERRY JAM FILLING

1. Place a small plate in the freezer - this will be used to test your jam. Place the berries and sugar in a large saucepan, and mix to combine. Allow to sit for 30 minutes. Add the vanilla bean paste and salt
2. Place the saucepan over medium high heat, and mash the berries using a potato masher. Heat, stirring frequently, until the mixture comes to a boil, then cook for a further 10 to 15 minutes, until it has thickened slightly and passes the “wrinkle test” - when you put a little onto the plate in the freezer and freeze for a minute, if you nudge the jam, it should wrinkle if it is done.
3. Add the lemon and mix to combine. Transfer to a clean jar, cool, and store in the fridge until needed.

VANILLA BEAN SWISS MERINGUE BUTTERCREAM

1. Place the egg whites, sugar and salt in the bowl of a stand mixer or a heat proof bowl. Place over a pot of simmering water, ensuring that the water does not touch the bowl. Heat, whisking constantly, until the mixture registers 160˚f / 70˚c on a thermometer and the sugar has dissolved. Carefully transfer the bowl to the mixer, and fit with the whisk attachment.
2. Whip the egg whites on high for 8-10 minutes, until they hold a relatively stiff peak. Add the butter one chunk at a time. The mixture may look curdled - but just keep mixing! Once all the butter is incorporated, mix on high for a further 5 minutes. Add the vanilla and mix until incorporated.
3. Once the buttercream has finished mixing, and is smooth and silky, mix for a further 2-3 minutes, then switch to the paddle attachment and mix on low for one minute to remove any air.

ASSEMBLY

1. Transfer some of the buttercream to a piping bag fitted with a medium round tip - this will be used to make a buttercream dam to hold in the passionfruit filling between layers. Using a sharp knife, cut the cake horizontally into two pieces.
2. Place the first layer of cake into the cake pan, then top with about a cup of the Swiss meringue buttercream. Pipe a ‘dam’ around the outside of the cake using the piping bag, then fill in using the mixed berry jam filling. You will likely not need all of it - store remainder in the fridge.
3. Top with the second layer of cake, and spread a smooth layer of buttercream over the top surface of the cake. Place in the fridge or freezer while you prep the buttercream topping.
4. Divide the remaining buttercream into 4-5 bowls, and tint into various shades of your desired colour using gel food colouring. Transfer to piping bags fitted with various piping tips of your choice - I used Wilton 104, 199, 1M, 4B and 6B.
5. Pipe a combination of rosettes, wriggles (using the 104 tip), and blobs onto the surface of the cake - I found that it was best to pipe the rosettes and wriggles first, then fill in with the blobs.
6. Chill well - allow to come to room temperature an hour before serving. Cut with a sharp knife, wiping the blade between cuts.
7. Store leftovers in an airtight container in the fridge.