Place washed whole oranges in deep pot of water and place on stove. Bring to boil and boil for 2 hrs refilling pot when neccessary. This is to soften the oranges and take some of the bitterness out of the pith.

Remove oranges and break apart with a spoon. Leave until cooled.

Preheat oven to 180°C gas oven. Line a spring form cake tin with baking paper and spray lightly with oil spray

Whisk the eggs in a bowl until almost combined. As the whisk is running, gradually add the sugar to ensure it dissolves well. Continue to whisk until pale and creamy.

Separate the orange flesh from the skin, discarding any seeds. Place flesh and any juice into a blender. Add all the orange skin unless it is thick and quite bitter. In that case add only the skin of 1 orange.

Blend the oranges until smooth. Add this to the eggs along with the nut meal, vanilla & baking powder. Fold gently until well combined.

Pour batter into cake tin and sprinkle extra sugar on top for a caramelised crust. Bake for 1 to 1 1/2 hrs until golden brown and a skewer comes out clean.

Enjoy hot or cold! Yummy with no butter goodness!