Updated: Nov 17, 2020
Serves: 8 - 10
Time: 1 – 1 1/2 hours plus cooling
20cm x 20cm square cake tin
For the sponges:
· 75g Walnuts
· 250g Salted Butter - softened
· 250g Caster sugar
· 4 large eggs, lightly beaten
· 275g Self-raising flour
· 1tsp Vanilla extract
· 4tsp Good quality instant coffee dissolved in 2-3 tsp boiling water
· 1tsp Cocoa powder, mixed with 1 tbs of hot water
For the buttercream:
· 125g Unsalted butter - softened
· 250g Icing sugar – sifted
· 2 tbs Double cream
· 1 tsp Good quality instant coffee dissolved in a little boiling water – more to taste
For the assembly:
· 500g Marzipan (you can make your own)
· 2tsp Cocoa powder
· 50g Dark chocolate melted and cooled
· 100g Caster sugar
· Walnut halves
You will need an 8” square cake tin, greased and lined then divided into two oblongs with folded baking paper, you don't need a special tin
1. Preheat the oven to 160C Fan
2. Put the walnuts into a dry frying pan and toast them for a few minutes until they smell toasty, keep an eye on them they can
burn. Remove from the heat and finely chop. You can use a food processor but be careful you want small pieces not dust.
3. Cream together the softened butter and sugar, add the eggs, flour and vanilla and beat for about 1 minute until completely combined.
4. Divide the cake mixture into two bowls, weighing to get equal amounts.
5. Stir the walnuts into one bowl, add a little milk or boiling water to get a soft dropping consistency. Put the batter into one half of the prepared tin.
6. Add the dissolved coffee and cocoa powder to the second half of the batter and fold together, adding a little milk or hot water if necessary to get a soft dropping consistency. Put mixture into second half of prepared tin.
7. Bake in preheated oven for 25 – 30 minutes or until a toothpick inserted into the middle centre of the cakes, either side of the divide, comes out clean. If one side cooks faster than the other turn the tin round and keep checking every couple of minutes.
8. Remove from the oven, leave to cool in the tin for 10 minutes then remove to a cooling rack and leave to cool completely.
9. It would now be best to wrap in foil and pop it in the fridge for a couple of hours to firm up so that you can cut it cleanly.
10. To make the buttercream, whip the butter then stir in sifted icing sugar, coffee and double cream. When the danger of icing sugar cloud has passed whip the buttercream until soft and fluffy. Taste and add more coffee if necessary.
11. To flavour the marzipan simply knead the marzipan with the melted chocolate and cocoa powder. It may take it a while to get it smooth but its worth it.
12. To make the caramelized walnuts put the sugar in a saucepan and melt on a very low heat, as there is no water in it you can stir. It is so much easier to gauge the colour of the caramel in a steel or white pan. When the sugar has turned into a soft caramel colour remove from the heat. Spike a nut with a cocktail stick and dip into the sugar. Place on a sheet of baking paper or silicone. Leave to set.
13. To assemble trim the sponges so you have four equal rectangles with square faces. Sandwich them together with buttercream alternating the flavoured sponges. Coat the outside of the assembled sponges with buttercream on three sides and put into the fridge to firm up. When firm enough to handle turn the cake over and coat the fourth side with buttercream, now back in the fridge for 10 minutes.
14. Now measure the length and circumference of the cake. The circumference is easy if you use a piece of string to wrap round. Now roll out the marzipan on a piece of baking paper to the size of the cake. Place the buttercream covered cake in the centre of the marzipan and wrap round the cake using the baking paper to help. Flip over so the seam is on the bottom and trim.
15. Pipe some buttercream along the top and decorate with caramelized walnuts.