Wash the ‘fluffy coating’ from the fruit, de-seed and peel. Place the seeds in a muslin bag. Stew the fruit and seed bag with around a cup of water until soft. Remove the seed bag. Puree the fruit.
Weigh your quince puree. Place in the slow cooker with an equal weight of white sugar.
Cook in the slow cooker, stirring occasionally until the colour changes and the mixture thickens. Place in sterilised jars or containers. Can be frozen.