Put diced quince into slow cooker. Add sugar and mix through so all of quince is coated with sugar.
Turn slow cooker onto low. Cook for 9 hours, stirring now and again to make sure it is cooking evenly.
Turn off to allow quince mixture to cool a little (for safety reasons) then using a stab blender or a blender process till smooth. Cook on low for another 2-4 hours until nice and thick. Stir every 15 mins to make sure of even cooking. (My cheap slow cooker is hotter at one end.) When happy with thickness of cool paste turn off and bottle into sterile jars,
Basically weigh diced quince and use half the amount of sugar. Easy.
This is a fabulous recipe. Very easy. I stired it once an hour and found it only needed one more hour of cooking after I had whizzed it at the seven hour mark. I guess it depends how cool the slow cooker is. - 13 May 2015