Step 1

Cook quince in a saucepan of simmering water over medium-high heat until tender (15-20 minutes), then drain, reserving 250ml cooking liquid and set aside. Weigh quince and combine with an equal amount of sugar, then blend in a food processor with reserved liquid and vinegar until smooth. Pass through a coarse sieve, pressing to extract as much liquid as possible, then return to a saucepan over low heat and stir, occasionally at first, then continuously, as the mixture thickens until it holds a trail when you pass a spoon through it and is a deep pink colour (1½-2 hours). Transfer to a lightly oiled 20cm round cake tin and set aside at room temperature to cool, then refrigerate to set (2-3 hours). Membrillo will keep refrigerated for 2 weeks.

Step 2

Serve membrillo with Manchego, crackers and muscatels.