Preheat oven to 180c.
Wash and boil the oranges (unpeeled) in a little water for nearly 2 hours (or ½ hour in a pressure cooker).
Let them cool, then cut them open and remove the pips.
Turn the oranges into a pulp by putting them in a food processor or an electric blender.
Whisk the eggs in a large bowl.
Add all the other ingredients, mix thoroughly and pour into a buttered and floured cake tin with a removable base if possible.
Bake in a preheated oven for c 30 minutes.
If it is still very wet, leave it in the oven for a little longer.
Cool slightly in the tin before turning out.
Dredge with icing sugar.
