Preheat the oven to 180°C.
Peel and core the apples, then chop roughly into bite-sized chunks.
Put the apple, water, lemon juice and half of the sugar in a saucepan. Bring to the boil and cook for 5 minutes until tender. Mix in half of the cinnamon, the raisins and vanilla.
Transfer to an oven-proof dish.
Rub the margarine with the flour and cinnamon until you get fine breadcrumb-like crumbles, then add the oats and the leftover sugar.
Cover evenly the apple mixture with the oat crumble, slightly pressing the top with a spoon.
Bake for 20-25 minutes until the top is golden and crispy.
Serve it warm with dairy-free ice-cream, custard or yoghurt.