Chocolate, hazelnut and salted caramel cake

To roast the hazelnuts:

• Preheat the oven to 200°C/180°C fan/Gas 6. Spread the hazelnuts out on a large baking tray and toast for 5 minutes or until lightly golden and smelling ‘nutty’. Tip out onto a plate and allow to cool completely.

To make the chocolate sponges:

• Preheat the oven to 180°C/160°C fan/Gas 4. Grease and line two 20cm round cake tins with baking paper.
• Sieve the sugar, flour, cocoa, bicarbonate and salt into a large mixing bowl the mix together.
• Measure the oil, coffee, water and vanilla into a large jug and whisk together. Pour over the flour mixture and whisk everything together until smooth and glossy. Finally whisk in the eggs.
• Weigh out 100g of the roasted hazelnuts and finely chop. Stir these through the cake batter. Divide evenly between the two tins and bake for 25-30 minutes or until the cakes are a pale golden colour and feel springy to the touch. Cool in the tins for 10 minutes then carefully turn out onto a wire rack to cool completely.

To make the salted caramel:

• Add the sugar and water to a medium saucepan and place over a medium heat. Bring to the boil without stirring, swirling the pan every now and again to help the sugar dissolve and stop any sticking to the sides.
• Once the sugar has dissolved, allow to boil until the mixture just starts to turn golden at the edges. Swirl the mixture and let it bubble away until the whole mixture is an even golden caramel.
• Remove from the heat and pour in the cream, being careful as it may splutter as it hits the hot caramel. Stir gently to combine and it should reduce to a gentle bubble.
• Add the butter and salt and keep stirring until smooth. Pour into a bowl and leave to cool.

To make the hazelnut Italian meringue buttercream:

• Place the remaining 150g roasted hazelnuts in a small blender or food processor and blitz for a few minutes until it becomes a paste, like peanut butter.
• Whisk together the egg and yolks until thick and creamy – it’s best to do this in a stand mixer with a whisk attachment. The whisk should leave a thick trail or ribbon when you lift it out.
• Put the sugar and water in a small pan over a medium-high heat. Allow the sugar to dissolve then increase the heat to high and bring to a boil. Insert a sugar thermometer and bring the syrup up to 118°C.
• Start the whisk again in the egg mixture then slowly pour in the hot syrup, whisking continuously. Keep whisking until all the syrup is incorporated and the bowl is no longer hot to the touch.
• Add the butter, a cube at a time, while you continue to whisk. Once all incorporated the mixture will be thick and glossy.
• Stir through the blitzed hazelnut paste.

To make the decorations:

• Roughly chop or break the chocolate into pieces. Place in a heatproof bowl set over a small pan of barely simmering water – being careful not to let the base of the bowl touch the water. Leave to melt, stirring occasionally until smooth.
• Line a baking tray with baking paper. Use a pastry brush to paint long stripes of melted chocolate onto the paper – you’ll need about 12-14 to go around the cake and can vary the sizes so some are longer than others. Chill in the fridge to set.
• Transfer the remaining melted chocolate to a piping bag. Line a small bowl with cling film and grease with a little oil.
• Pipe thin lines across the bowl one way then the opposite way to create a criss-cross lattice all over the base and up the sides – this is your ‘nest’. Place the whole bowl in the fridge to set.

To assemble the cake:

• Place one of the sponges on your serving plate or board. Spread about a third of the buttercream over the top of the cake. Make a slight ridge around the edge of the buttercream then spoon the salted caramel into the middle and spread over to fill the centre up to the ridge.
• Place the second sponge on top. Cover the whole cake with the rest o the buttercream, spreading over the top and around the sides with a palette knife to create a smooth finish. Don’t worry if it’s not completely smooth, you’ll be covering the sides with the chocolate stripes. 
• Carefully peel the chocolate stripes off the paper and press gently around the sides of the cake. 
• Lift the chocolate nest out of the bowl using the cling film, then carefully peel off the cling film. Place in the centre of the cake and fill with mini chocolate eggs.