Preheat oven to 170C (340F). Grease an 8 or 9 inch round pan.
Wash the oranges, place them in a large saucepan and cover with water. Bring to boil and simmer for 15 minutes. Drain, then return to pan, cover with water and bring to boil. Let simmer another 15 minutes. Drain and coarse chop the orange discarding any seeds.
Place the oranges in the bowl of a food processor and process until smooth.
Whisk the eggs and the sugar until thick and pale. Add the orange, almond meal and baking powder and fold until just combined.
Pour into a greased, 22cm round pan and bake in 170C (340F) for about 50 minutes or until skewer inserted comes out clean.