1 Place the oranges in a large saucepan, and add enough water to cover. Bring to a boil, and boil for 2 hours over medium heat. Check occasionally to make sure they do not boil dry. Allow the oranges to cool, then cut them open and remove the seeds. Process in a blender or food processor to a coarse pulp.
2 Preheat the oven to 375 degrees F (190 degrees C). Grease and flour a 10 inch round cake pan.
3 In a large bowl, whip eggs and sugar together using an electric mixer until thick and pale, about 10 minutes. Use a whisk attachment if available. Mix in baking powder, and saffron if using. Stir in the pureed oranges. Gently fold in almond meal, and candied orange peel if using; pour batter into the prepared pan.
4 Bake for 55 minutes, or until a small knife inserted into the center comes out clean. Allow the cake to cool in the pan. Tap out onto a serving plate when cool.