| 1 | Preheat oven to 190°c. Lightly spray a 22cm springform tin with cooking spray and line with baking paper. Scrub oranges and limes. Place oranges in a large saucepan of boiling water and simmer for 1 hour. Add limes and continue cooking for 1 hour or until fruit is very soft. |
| 2 | Remove fruit from water and allow to cool. Cut fruit in half and remove seeds. |
| 3 | Place fruit, including skins into a blender or food processor and blend until smooth. |
| 4 | Using an electric mixer or hand blender, beat eggs, egg whites, sugar and baking powder until thick and pale. |
| 5 | Fold in almond meal and pureed fruit mixture. |
| 6 | Spoon mixture into tin. Bake for approximately 1 hour or until a skewer comes out clean. Place cake tin on wire rack and allow to cool. |
| 7 | Serve with whipped cream if desired. |