Rinse the quinoa under hot water and drain. Place the quinoa, 200ml water and the milk in a saucepan, bring to the boil and simmer, covered, over a low heat for 15 minutes. Turn off the heat and leave to soak, covered, for another 5 minutes. Allow to cool.
Meanwhile, grate a quarter of the orange zest.
Separate the eggs. Beat the egg whites until stiff, then gradually whisk in the sugar.
Mix the egg yolks, quark and quinoa and season with orange zest, cinnamon and ginger. Fold in the egg whites and sweeten to taste.
Brush a casserole dish with oil and spoon in the quinoa mixture. Bake in a preheated oven at 200°C (180°C fan, gas 6) for 30 minutes.
Meanwhile, peel both oranges and cut out the segments. Collect the juice. Coarsely chop the raisins. Mix the orange segments with the raisins and orange juice.
Wash, quarter and core the apple. Peel and halve the kiwi. Cut both into slices and mix with the orange segments.
Peel the bananas, cut into slices and mix with the other fruits. Let the fruit salad soak for 10 minutes and serve with the quinoa cake.