You will enjoy this one!
Preheat the oven to 180°C. Place the apple in a small saucepan with enough water to come about half way up the amoung of the apple (not covering the apple). Simmer gently until apple is starting to soften. Then add the frozen pitted cherries and cook until they are just soft.
While the apple is cooking combine the dry ingredients and mix in the butter to form the crumb for the topping.
Turn the apple and cherries into the bottom of a 24 cm round pie dish. Top with the crumble topping and bake until golden and bubbling. Cover the crumble after 10 minutes or so to prevent it from catching.
Serve warm with yoghurt, double cream or coconut yoghurt.