Preheat the oven to 180°C.
Slice the rhubarb into 3cm pieces and place into a deep saucepan along with the juice of one of the oranges. Peel and segment the remaining two oranges and add to the pan. Sprinkle over the ginger and coconut sugar and stir to combine. Bring to a gentle simmer and cook for five minutes until the rhubarb has just begun to soften.
Meanwhile, tip the oats, spelt flakes, puffed quinoa, almonds, cinnamon and salt into a mixing bowl. Place the honey and coconut oil in a small pan and warm over a moderate heat until both have melted. Pour this over the cereal and nut mixture and stir well to combine.
Pour the cooked rhubarb and oranges into an ovenproof dish and sprinkle the crumble mixture over the top. Place the dish into the oven and bake for 20 minutes until the topping is golden and crisp and the fruit is nicely bubbling at the sides. Serve with a dollop of fresh organic yogurt.