5-ingredient flourless orange and almond cake

This cake is so easy and incredibly tasty and moist, given the whole orange goes into it.Well worth having in your repertoire and delicious served with creme fraiche and dark berries

2 large oranges
6 large organic eggs
½ lb ground almonds (also called almond flour)
½ lb sugar
1 tsp baking powder

Wash the whole oranges and simmer them, unpeeled, in water to cover for 2 hours. Cool, cut them open and remove the seeds. Puree the oranges, including the peel, in a food processor.
Preheat the oven to 400 degrees.
Beat the eggs in a food processor or large bowl. Add the remaining ingredients, including the orange puree, and mix thoroughly. Pour into a buttered and floured cake tin, with a removable base if possible.
Bake for one hour, or until a knife inserted in the center comes out clean. Cool in the tin before turning out.