Chocolate, blood orange and hazelnut cake

Method

1. Put the 2 blood oranges in a large pan, cover with water, bring to the boil, then simmer for 2 hours, topping up the water where necessary. When they’re nearly done, heat the oven to 180°C fan/gas 6. Put the hazelnuts on a roasting tray and toast in the oven for 10 minutes, shaking the tray halfway through, until evenly golden and shining with their natural oils.
2. Transfer the nuts to a food processor and whizz in pulses until fine – try to get them as fine as possible but don’t whizz for too long, otherwise they’ll start to turn into nut butter. Drain and roughly chop the oranges, remove any pips, then add to the food processor (skins and all). Whizz again until smooth. Add the rest of the cake ingredients (except the crème fraîche) and whizz once more until you have a smooth, dark batter flecked with orange.
3. Turn the oven down to 160ºC fan/gas 4 and line the cake tin with baking paper. Pour the cake batter into the tin, then bake for 50-60 minutes, covering with foil if it starts to darken too much on top. A skewer pushed into the centre should come out clean when it’s ready.
4. While the cake bakes, make the topping. Slice the peel off the orange, trying to avoid as much white pith as you can (although don’t worry too much). Cut the peel into thin strips, then put in a small saucepan with 60g of the sugar and 60ml water. Bring to the boil, simmer for 10 minutes, then drain (keep the syrup to use in a cocktail) and leave to steam-dry for a bit. Toss with the remaining sugar.
5. Leave the cake to cool in the tin for a few minutes, then carefully remove it and scatter the orange peel on top (if you’re transporting the cake, leave it in the tin, then remove it and decorate with the peel when you arrive). Serve as is or with a dollop of crème fraîche.