Vanilla Layer Cake

CAKE LAYERS

1. Preheat the oven to 350°f / 180°c. Grease three 8” cake pans, and line with parchment paper on the bottom.
2. In a medium bowl, whisk together the eggs, egg yolks, vanilla, milk, and yoghurt.
3. In the bowl of a stand mixer fitted with the paddle attachment, combine the flour, sugar, baking powder, and salt. Mix briefly to combine.
4. With the mixer on low, add the butter a cube at a time, until fully incorporated and the mixture looks like sand.
5. Add half of the wet ingredients into the mixer. Mix until just combined, then add the second half of the wet ingredients. Mix on medium speed until just combined. Remove the bowl from the mixer and give a few folds with a rubber spatula to ensure that no dry ingredients remain.
6. Divide the batter between your three cake tins (I prefer to do this by weight - see notes). Bake for 35 to 40 minutes, or until the cakes are springy to the touch, and a skewer inserted into the middle comes out clean.
7. Remove from the oven and cool for 15 minutes in their pans, then turn onto a wire rack and allow to cool completely.

PASSIONFRUIT CURD FILLING

1. Place the Passionfruit pulp in a blender or food processor. Pulse a few times to separate the seeds from the pulp. Strain through a sieve into a medium saucepan. Reserve the seeds.
2. Add the remainder of the ingredients to the saucepan, and place over medium heat. Whisk well to combine. Place over medium low heat, and cook for 30 minutes, stirring frequently, until the curd has thickened significantly - enough that it coats the back of a spoon well, and when you run a finger through, it leaves a very clear track.
3. Strain through a fine mesh sieve into an airtight container, and stir in 1-2 Tbsp of the reserved passionfruit seeds. Place a piece of plastic wrap over the surface of the curd. Refrigerate until completely cool, ideally overnight.

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 until they are snowy white and fluffy, 8-10 minutes. 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 10 minutes. Add the vanilla and mix until incorporated.
3. Once the buttercream has finished mixing, and is smooth and silky, add in the vanilla bean paste. 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. Level off the cake layers. 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.
2. Secure one of the layers of cake to a cake turntable using a little buttercream. Add about a cup of buttercream onto the first layer of cake, and smooth using an offset spatula. Create a buttercream dam using the buttercream in the piping bag by piping a ring of frosting around the outside edge of the first layer.
3. Fill in the ring with approximately 1/2 cup of the passionfruit filling. Place the second layer of cake onto the first, pressing very lightly to secure, and sealing the joins with a thin layer of buttercream. Repeat the layering process - add a cup of buttercream, make a dam, fill with 1/2 cup hazelnut filling, then top with the third layer of cake - I like to put this one upside down to ensure that the top of the cake is flat. Return the rest of the buttercream in the piping bag to the bowl with the buttercream.
4. Crumb coat the cake - to do this, apply a thin layer of buttercream over the surface of the cake, and smooth with a bench scraper or icing smoother. Refrigerate the cake for 30-45 minutes, until the crumb coat has set.
5. Divide the Remaining buttercream 2/3 to 1/3. Colour the 1/3 portion with gel food colouring to your desired shade.
6. Create an ombre effect by spreading the bottom 1/3 of the cake with yellow buttercream using an offset spatula, and the top 2/3 with white. Blend the middle section by spreading blobs of white and yellow. Spread buttercream on the top of the cake using an offset spatula.
7. Smooth the buttercream on the outside of the cake using a bench scraper, scraping down between passes. Fill in any gaps, and add additional colour where needed to give you a nice transition of colour. Continue until you are happy with the finish.
8. Transfer the remainder of the buttercream (both yellow and white) into a piping bag fitted fitted with a Wilton 1M tip or similar. Pipe blobs onto the top of the cake - using the 1m tip you only need to pipe blobs rather than making a swirl - the tip makes the ruffles for you.
9. Chill the cake until ready to serve. Remove from the fridge about an hour before serving to bring to room temperature.
10. Store leftovers in an airtight container in the fridge