Put 4 mandarins in a saucepan, cover with cold water then simmer for 25 minutes. Drain and slightly cool the mandarins, then blend in a food processor until; you get a rough textured purée.
Preheat the oven to 180C. Grease a spring-form cake tin with oil and line the base with baking paper.
In a large bowl, using an electric whisk, cream the egg yolks and half the sugar.
In another bowl, whisk the egg whites until stiff, then whisk in the rest of the sugar.
Fold the puréed mandarins, ground almonds and mixed spice into the egg yolk mixture.
Fold a little egg white into the mixture, then gently fold in the rest.
Transfer the mixture into the cake tin and bake for about an hour, until it's golden and an inserted skewer comes out clean.
Leave the cake to cool in the tin, then turn it out onto a plate.
Prick the top of cake several times with a skewer.
Peel & slice 3 or 4 mandarins. Put these on top of the cake and drizzle over some maple syrup. Let the juices sink into the cake.
Dust with icing sugar just before serving.