Membrillo is the Spanish word for quince but is commonly used to denote Spanish quince paste or 'cheese', a coral-pink jellied preserve with a delicate floral taste. Although they're not commonly eaten raw, quinces are especially high in pectin, the ingredient that 'sets' fruit pulp, so they make particularly good preserves such as this.
IN THE KITCHEN
Membrillo's classic match is the Spanish sheep's milk cheese manchego, however it's also delicious served with other varieties. Cut it into cubes and offer it to guests as an after-dinner sweetmeat alongside walnuts and glasses of Oloroso sherry, or with ice cream, yogurt or cream as a dessert. Membrillo is an interesting ingredient in cooking, too: use it in tarts and puddings as you would jam, or add a spoonful to sweet-savoury pan gravies and glazes as you would redcurrant jelly - it works well with fatty meats such as lamb, pork and duck. If you have access to a glut of quinces, you can make membrillo at home with sugar and lemon juice, adding a stick or two of cinnamon if desired.
Very similar products are made in other countries: most notably Britain, which has a long tradition of making 'fruit cheese' (this includes quince recipes as well as damsons, blackberries, and so on) and Mexico, which is historically connected to Spain and makes membrillo-style pastes from fruits including guava and mango.
Simply cut membrillo into thin wedges, slices or cubes to serve.