The hardest part of making this cake is waiting until it cooled down. Of course we did not manage to do so and warm it is also delicious; but it is best when the chocolate is completely hard. Using the entire orange, including the peel, gives the tart an incredible rich orange flavor, and I like to think that it also keeps some vitamins, or am I just kidding myself? —Janneke Verheij
Boil the oranges in water with a teaspoon of orange blossom for 1 hour.
Preheat the oven to 160 C/ 320F. Take a round cake form about 24 cm/10 inch diameter; grease it with butter and dust it with flour.
Puree the whole oranges, peel and all, in a kitchen machine with the whipping cream until almost smooth.
Separate the eggs and mix the egg yolks, sugar and vanilla sugar until light and creamy; now add the orange puree and the Greek yogurt and mix well. Bit by bit sift the flower with baking powder and bicarbonate of soda over the mixture and mix until all is incorporated in the mixture.
Beat the egg whites until cloudy (you have to be able to turn the bowl upside down without the egg white gliding out). Carefully fold the egg whites into the mixture.
Pour the mixture in the form and bake for about one hour or until a toothpick comes out clean.
When the tart is cooling down, melt 200 grams of pure chocolate ‘ au bain-marie’ with half a spoon of butter and poor it over the tart. Let the chocolate cool down in the fridge.