Put the oranges in a small saucepan, cover with water, and simmer gently for two hours. Remove from the water and cool.

Whiz the almonds and sugar in a blender until they are coarsely ground. Set aside. Put the whole oranges in the blender and mush them till smooth. Mix in the eggs, one at a time, until combined. Add the almonds and sugar, baking powder and vanilla. Blend until combined. Pour the mixture into a greased cake tin and bake at 150 C for one hour.

Shortly before the cake is ready, make the syrup by mixing the ingredients together and simmering for 5-10 minutes, until slightly thickened.

Remove the cake from the oven, and gently pour over the warm syrup. Let the cake cool before removing from the tin.