STAR BAKE Give the classic coffee and walnut cake a twist with caramelised praline nuts and mousse-y custard buttercream

The star baker Henry Bird gives this classic coffee sponge a twist with sweet praline nuts and smooth German buttercream

https://www.thetimes.com/recipes/baking-desserts/cake/article/coffee-walnut-praline-cake-recipe-dm2nf3l92



Nothing ruins a perfectly good cake more than a sickly, cloying buttercream. It can easily smother any other flavour you have worked hard to incorporate. If you have sworn off cake for this very reason, give this coffee and walnut praline cake a go. The buttercream is based on a fantastic recipe for German custard buttercream from Bernadette Gee’s book Magnolia Kitchen. It’s a variant of crème mousseline, a type of filling often used in French pastries, which is essentially custard whisked together with butter. The result is much silkier and less sweet than standard buttercreams, such as American, Swiss or Italian, which use either icing sugar or meringue as the sweet element. You will need two 18cm tins for this recipe. If you are feeling confident, slice each cake in half horizontally to give yourself four thin layers, or keep it as two.



Method

Step 1.
First make the sponge cake. Preheat the oven to 180C. Grease and line the base and sides of two round 18cm cake tins.
Step 2.
In a stand mixer, or using an electric whisk, beat together the butter and sugar until very pale and fluffy — about 7 minutes. Then gradually add the beaten eggs, mixing well after each addition.
Step 3.
Sift together the flour, baking powder and mixed spice onto a sheet of greaseproof paper. I usually do this a couple of times to make sure there are no lumps and to aerate the mixture. Then, while beating your cake mixture, add the flour mix a spoonful at a time. Follow with the milk and the coffee.
Step 4.
Toss the walnuts in a teaspoon of flour. I find this helps to stop them from sinking to the bottom of the cake. Then fold these through the mixture.
Step 5.
Evenly divide the mixture between the cake tins. Give each a bang on your work surface to remove any big air bubbles, then bake for 20-25 minutes, or until a toothpick inserted into the middle comes out clean. Leave the cakes to cool in their tins for 10 minutes, then turn out onto a wire rack to cool completely.
Step 6.
Meanwhile, make the buttercream. In a heatproof bowl, whisk together both sugars, cornflour, eggs and vanilla until thick and well combined.
Step 7.
In a pan over a medium to low heat, bring the milk to a very gentle simmer, then slowly pour over the sugar mixture, whisking continuously. If the milk is too hot or is added too quickly, the mixture could curdle. Return the mixture to the saucepan, stirring continuously, and heat gently until it thickens and starts to bubble.
Step 8.
Transfer the hot custard mixture to a stand mixer, and whisk on high speed until the bowl is cool to the touch. With the whisk still running, add the cubes of butter one at a time. The mixture may look split or runny at first, but once you have added all the butter it will come together into a silky smooth buttercream. If it looks too runny at this stage, you can put it in the fridge for a few minutes to firm up.
Step 9.
Swap the whisk for a paddle attachment, add the coffee, and mix on low. This helps to remove any big air bubbles and makes it even smoother.
Step 10.
To make the praline, toast the walnuts in a dry frying pan over a medium-high heat for about 5 minutes until they give off a beautiful, fragrant aroma and are slightly darker. Transfer to a baking tray lined with greaseproof paper.
Step 11.
Heat the caster sugar in a small saucepan over a medium-high heat, gently swirling the pan as it melts, until you have a rich, golden-brown caramel. Pour the caramel over the walnuts, sprinkle over a pinch of sea salt flakes and leave to cool. With a sharp knife, cut the praline sheet into small clusters.
Step 12.
To assemble your cake, spread a generous dollop of buttercream over the bottom sponge, then scatter over some praline clusters. Add your second sponge and pipe the buttercream for a more elegant finish.