Preheat the oven to 155°C (310°F) / 135°C fan / gas mark 3. Butter two 20cm springform cake tins and line the bases with baking parchment.
Spread the walnuts on a baking tray and toast in the oven for 20–25 minutes, turning every 5 minutes until golden brown.
Set aside to cool, then roughly chop.
To make the cake, combine the eggs, oil, and sugar in a large mixing bowl and whisk until smooth. You can also use a food mixer with the beater attachment.
Add the flour, baking powder, cinnamon, and salt to the wet and mix until just combined.
Fold in the raisins, mixed peel, toasted walnuts, and grated carrots until everything is thoroughly incorporated.
Divide the batter evenly between the two prepared tins.
Bake for 25–30 minutes, or until a skewer inserted into the centre comes out clean.
Allow the cakes to cool in their tins for 10 minutes before carefully turning them out onto a wire rack to cool completely.
To make the icing, ensure the butter and cream cheese are at room temperature.
Beat them together in a large bowl until smooth and creamy.
Add the sifted icing sugar and beat again until light and fluffy.
Fold in half of the blood orange zest and all of the blood orange juice.
Once the cakes are completely cool, place one layer on your serving plate.
Spread a layer of icing over the top, then place the second cake on top.
Generously coat the top of the cake with the remaining icing.
Sprinkle evenly with the remaining orange zest to decorate.
Using sunflower oil instead of butter is the key to a super moist cake crumb.
