Wash and cut the Quince in to small pieces. No need to peel or remove the core.
Put them in to the pan and add water so that the Quince is just covered and almost floating.
Put on to a gentle simmer and allow the fruit to completely soften. When you can see it softening you can help it along by mashing it a little.
When soft, place the pulp in a strainer and allow to strain for a few hours, squeezing the bag occasionally if you can see that the drips have halted.
When you think that the bag is no longer giving you any more liquid then pass the pulp through a fine mesh sieve. This will ensure that you get the most out of the Quince.
Weigh the juice/pulp you have retrieved and add it back in to the clean pan.
Add the same weight/amount of granulated sugar to the amount of pulp and put on to a gentle heat.
Stir until the sugar has dissolved and then continue to simmer gently, stirring often.
The mixture will begin to darken and bubble, ensure you do not boil it, but simmer gently and allow to thicken. You’ll know when it is ready as you will be able to pull the wooden spoon through the mixture, along the bottom of the pan, and the mixture will part for about two seconds before folding back in on itself.
Rub down the sides of your straight sided plastic tub with a small amount of sunflower oil and pour the mixture in to the tub.
Place some clingfilm over the top of the tub and then put the lid on.
Allow the tub to cool before putting in to the fridge to set proper.