Put the soy milk in a saucepan and bring to the boil with a pinch of salt. Briefly rinse the rice pudding in a colander with cold water and drain, stir into the hot soy milk. Let everything swell over a mild heat for approx. 35 minutes. Stir diligently again and again, it burns easily. At the end, possibly sweeten with vanilla sugar, as the soy milk is sweet anyway, maybe omit the sugar.
For the puree, peel, quarter and core the apples and cut into large cubes. Squeeze the lemon, add the juice and apple juice to the apples and bring to the boil with the sugar. Simmer gently over a mild heat for about 10 minutes, then puree. Refine with the cinnamon and serve with the rice pudding.