Pre-heat oven to 180°C. Grease and line a deep 20-25cm cake tin.
Boil mandarins in a large pot of water for about 1-11/2 hours, until soft.
Cool, remove pips and pure, skin and flesh until smooth.
Beat eggs and sugar until light and pale, about 6 minutes.
Add mandarin puree, almond meal and baking powder.
With an electric beater on low, mix until combined.
Spread batter into greased cake tin and bake for 55-60 minutes or until firm on top.
Cool the cake completely in tin, before removing.