Boil oranges, barely covered with water, in a covered saucepan for 2 hours.

Allow to cool, then cut open, remove pips and chop roughly, including the rind. Preheat oven to 190°C and butter and flour a 24cm springform tin.

Blend oranges and eggs thoroughly in a food processor.

Mix ground almonds, sugar and baking powder in a bowl, then add orange mixture and whisk to combine.

Pour batter into prepared tin and bake for 45 minutes – 1 hour.

If cake is still very wet, cook a little longer. Cool in tin before gently turning out.