1. Preheat oven to 200°C.
2. Place pears, rhubarb, 1 cup juice, sugar and vanilla paste in a deep pan over medium heat. Stir well and bring to a simmer. Cover and cook, stirring occasionally, until pears are just tender and rhubarb has collapsed (about 8 minutes). Transfer to a baking dish.
3. Put cereal in a plastic bag and bash with a rolling pin until a finer crumb forms. Place in a bowl and add oats and extra juice. Stir well to coat evenly, then spread over top of fruit in pan. Bake until crunchy and golden (about 12 to 15 minutes).
4. Serve warm crumble with yoghurt, if desired.
Nutritional Info Per serving: 1,326 kJ (317 cal), 5 g protein, 65 g carbs, 9 g fibre, 3 g fat, 1 g sat fat, 114 mg sodium