Quince is a delightful fruit, but rock-hard and more or less inedible when raw. One could eat them, but they are so hard and sour that the experience would be thoroughly unpleasant. Your mouth would feel like all the moisture was sucked right out of it in the most unappetizing way. So, in short, quinces are best eaten after being cooked.
Quinces are most often cooked down into jellies and jams and candies, but their bright flavor is also lovely when added to other fruits (an apple pie, for example) or served alongside roasted or stewed meats. As advised above, they need to be cooked first. An easy and flavorful way to do that is a gentle poach in simmering, slightly sweetened water.
To Poach Quince
- Cut the quince into quarters–cutting out the core–and then cut the quince into wedges or slices or chop as befits your recipe or final use (you can leave them in quarters if you like).
- Put the quince in a pot with enough water to cover all of the pieces. Add 2 tablespoons of sugar for each cup of water you add. Throw in a cinnamon stick, if that sounds good, for extra flavor and if it matches your final recipe (whole cloves, cardamom pods, and allspice are other tasty spices to add that will flavor the quince nicely).
- Bring the liquid just to a boil, stirring a bit as it heats to help the sugar dissolve. Reduce the heat to low and gently simmer until the quince is completely tender, about an hour. If you want to eat the plain poached quince (with ice cream, for example), cook them a bit longer so they can be cut with a spoon.
- Let the quince and the poaching liquid cool to room temperature. Use in a recipe or store, covered and chilled, for up to a week.
Note: If you want the syrup to be a bit thicker, remove the quince and boil the syrup until it reduces about a quarter to a third and thickens a bit. You can store the quince and syrup separately, but the quince will last longer in the syrup.