Apple Snack Cake with Ombre Walnut Praline Swiss Meringue Buttercream

APPLE CAKE

1. Preheat the oven to 350°f / 180°c. Grease and line a 9” square cake pan with parchment paper.
2. In the bowl of a stand mixer fitted with the whisk attachment, or in a bowl with an electric hand mixer, beat together the eggs and brown sugar on medium speed until light and fluffy.
3. Add the Extra Light Olive Oil and the Vanilla Bean Paste, and mix to combine. Add the apples and fold in using a rubber spatula.
4. In a medium bowl, combine the dry ingredients. Add to the mixture and fold in with a spatula until combined.
5. Transfer the mixture to the prepared cake pan, and smooth down. Bake for 50 minutes to an hour, or until a skewer inserted into the middle of the cake comes out clean.
6. Remove from the oven and allow to cool completely in the pan. 

WALNUT PRALINE

1. Measure out the walnuts into a bowl and have them nearby ready to go. Line a baking sheet with silpat or parchment paper.
2. Combine the sugar and water in a wide skillet or frying pan (stainless steel or something white is best so you can see the caramel).
3. Bring the water and sugar to a boil, and then cook on medium until the mixture registers 245°f / 118°c on a candy thermometer, washing down the edges with a pastry brush dipped in water as needed.
4. Once the syrup reaches temperature, add the walnuts. The mixture will crystallise and form a white coating on the outside of the walnuts - this is normal. Cook over medium heat, stirring very frequently, until the sugar eventually melts and turns into a golden brown caramel that coats the nuts. Watch carefully so that it does not catch.
5. Transfer to the prepared baking sheet and allow to cool.
6. Once cool, place the caramelised nuts into the work bowl of a food processor. Add the salt and the vanilla bean paste, and pulse to break down the nuts. Process the walnuts for 2-3 minutes, or until a smooth paste forms, scraping down as needed. Taste and add more salt if needed.
7. Transfer into an airtight container until ready to use.

WALNUT PRALINE 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. 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.
2. 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.
3. Remove a third of the buttercream and set aside. Add in the walnut praline to the remaining buttercream, and mix to combine. Remove half of of the walnut praline buttercream and set aside, then mix the cinnamon into the remaining buttercream to give you a darker brown shade.

ASSEMBLY

1. Spread the surface of the cake with a thin layer of the walnut praline buttercream.
2. Fit piping bags with a range of tips - I used a #104 tip for the wriggles, and then 3 Ateco #862 tips for the bloops. Transfer the buttercream into the piping bags.
3. Pipe a combination of wriggles (using the 104 tip), and blobs onto the surface of the cake - I found that it was best to pipe the wriggles first, then fill in with the blobs.
4. Chill well - allow to come to room temperature an hour before serving. Cut with a sharp knife, wiping the blade between cuts.
5. Store leftovers in an airtight container in the fridge.