Place the two whole oranges in a saucepan and cover with water.
Bring to the boil and simmer, covered, for 1 hour, ensuring that the oranges remain covered with water. Drain and cool. Chop the oranges into quarters, discard any seeds, then place the chunks into a blender and puree until smooth.
Preheat oven to 160/180°C. Grease and line the base of a 8inch round pan.
Beat the eggs with the sugar until thick and pale. Take out 1/3 of the eggs and set aside.
Then add the orange puree, ground almonds and baking powder and mix well with whisk. After everything is well combined, put the reserved 1/3 of beaten eggs back into the batter and fold.
Pour into prepared pan and bake for 1 hour. Leave the cake to firm up in the pan for 20 minutes then turn out, remove the baking paper and turn over to finish cooling right way up.
