1. Put the fruit and cinnamon sticks into a large pan. Cover with cold water then bring to the boil. Reduce the heat to a simmer then cover and cook for 1 and 1/2 hours.
2. Drain and leave to cool for a couple of minutes. Remove the cinnamon, cut the fruit in half and discard the pips. Purée the fruit, including the peel, in a blender until smooth then set aside.
3. Preheat the oven to 180°C. Line a 23cm round spring form tin with baking paper.
4. Using an electric hand whisk, whisk the eggs and sugar in a heatproof bowl set over a pan of simmering water for 5 minutes until pale and mousse-like. Sift the plain flour and baking powder together in a large bowl then add the almonds and clementine puree. Gently fold in the sugar and egg mixture until smooth.
5. Transfer to the tin and bake for 20 minutes and reduce the oven temperature to 160ºC and bake for another 30 minutes or until a skewer inserted in the middle comes out clean.
6. Leave to cool in the tin for 15 minutes, then transfer to a wire rack to cool completely.
For the syrup:
1. Combine the pomegranate juice and sugar in a medium saucepan, bring to the boil then reduce the heat and simmer for 2 minutes. Remove from the heat and leave to cool slightly then add the orange blossom water and vanilla bean paste.
2. Using a pastry brush, imbibe the cake with the pomegranate syrup.
3. Warm the apricot jam and 1 tbsp water in a saucepan until smooth then brush over the cake. Scatter over the pomegranate seeds and finish the cake with a light dusting of icing sugar.
4. Serve with some stewed winter berries and crème fraîche.