Fruit Curds

Mid-winter can be a discouraging time of year to be a home cook. We're tired of all things stewed and braised but unless you live in Florida or California, it's too soon for local produce. Still, there's a prize in our end-of-winter markets and it's citrus.

Citrus may not be a local crop for most of us, but who can resist the uniquely sharp, sweet flavors that come from lemons, limes, oranges and grapefruits?

Only five or so years ago it was rare to find anything other than Eureka lemons, Persian limes, tangerines, and naval oranges at our markets. But now even a clementine can seem ordinary since we can easily also buy blood oranges, key limes, Meyer lemons, Cara Caras, Satsumas, star ruby grapefruit, and tangelos.

One of the best ways to cook with citrus is to make curd. It's a word that may first conjure an image of spoiled milk.  But a fruit curd is smooth, sweet, pudding-like and intensely flavored. It's used as a topping, as when it's spooned over a slice of pound cake. Or as a spread for scones or toast just as you'd use strawberry preserves. Or as the foundation for a dessert, as in lemon meringue pie where a pie crust is filled with lemon curd and then topped with sweet white meringue.

Making Fruit Curds

Fruit curds are made by combining fruit juice with egg yolks, sometimes whole eggs, and sugar, which are cooked over medium low heat until thickened. Then unsalted butter and sometimes fruit zest are added and the finished curd is cooled. Some recipes will call for thickening agents such as flour or cornstarch, but for the purest, brightest flavor -- which is the hallmark of a curd -- it's best to forego the thickeners and trust that the combo of egg, acidic fruit juice, and butter will achieve the right thickness without curdling.

Lemon curd is the best known and you can buy it by the jar, sold alongside jams, jellies and marmalades. But the store bought pales compared to a freshly made curd. Plus, there's no need to limit yourself to lemon (although it is my absolute favorite) since fruit curds are also made with limes, oranges, grapefruit, passion fruit, mangoes, cranberries, gooseberries, and even apples.

A successful curd not only achieves a thick consistency -- more like a pudding than a sauce -- but it also has acutely intense flavor that balances fruit juice and sugar. If too much sugar is used, the fruit flavor will be masked; if not enough, the curd will lose its sweet complexity.

Fruit curd usually uses freshly squeezed juice, certainly if it's a citrus curd. But for some fruits, as with passion fruit, you can use a good quality bottled or boxed juice or nectar.

But this is key: before making any fruit curd you need to taste the juice first. One orange can be much sweeter or more sour than another; same thing for limes, lemons or any fruit you're planning to use. So taste the juice first and add the sugar to the juice gradually, tasting along the way until you reach the right balance. Then add the sugared juice to the pan with the other ingredients and begin cooking.

We've added recipes for making curds with lemon, lime, and blood oranges. If you decide to swap out regular lemon juice with that from Meyer lemons, remember to reduce the amount of sugar because Meyer lemons are sweeter. Likewise for the limes if you use key limes. And because blood oranges can vary greatly in their sweetness or sourness, taste them first, too.  See our links to these three recipes:

• Lemon Curd. The classic and probably most versatile of all fruit curds.

• Lime Curd. Its pale green color and tangy flavor is a nice alternative to lemon.

• Blood Orange Curd. Depending on how dark red the juice, this curd can become a beautiful pink color that is appealing when spooned over a wedge of bright white angel food cake.

While some curd recipes call for using a double-boiler, I just use a heavy bottomed 3-quart saucepan and have never had a problem with burning or scorching. But remember to stir constantly and don't walk away from the pan, even for a moment. If you use a wooden spoon to mix the curd while it cooks, it will be easier to know when it's thickened by turning the spoon over and running your finger down its back; if your finger leaves a clear ribbon, the curd will be properly cooked. But achieving this state can take 10 minutes so don't raise the flame too high and be patient because otherwise your curd could turn out soupy.

A Twist On An English Classic

I invariably think of English high tea when I think of lemon curd. Spread on warm scones, maybe with a gild of the lily with some clotted cream, lemon curd is a classic British sweet. There is probably no one who knows the art and science of English preserves better than Pam Corbin. She is a master preserver who wrote The River Cottage Preserves Handbook (hardcover with color photos, Ten Speed Press © 2008, 2010), named for the farm established by British cookbook author and food personality Hugh Fearnley-Whittingstall.

Ms. Corbin's is an appealing and useful little book that combines technical lessons with wisdom and a pantry full of sweet and savory recipes, including this one for Apple Lemon Curd that she describes as "softly sweet, tangy, and quite, quite delicious."  See our link.

Storing and Using Fruit Curds

If you make citrus curds at the end of the winter it's a way to capture the big, bright taste from lemons, limes, oranges and grapefruit before the season ends and their flavor fades.

Once you have a cup or so of fruit curd, there's many ways to use it. And because its flavor can be intense, it can be used as a flavoring with other ingredients. Here are just a few ideas:

• Add to buttercream recipes to boost the flavor of cake icings.
• Mix with yogurt or whipped cream to make a quick pudding.
• Spoon it over slices of pound cake and layered with fresh berries to make a triffle.
• A pre-baked piecrust can be filled with curd and topped with whipped cream for an old-fashioned icebox pie.
• Sandwich a spoonful in between butter cookies.
• Drizzle a little over a meringue shell and top with whipped cream.
• Spread a little over toasted whole wheat or brioche bread to turn breakfast into dessert.
• Spoon over a thick slice of angel food cake.
• Bake individual tarts with a shortbread dough and fill with curd.
• Serve with pancakes or waffles and top with a sprinkle of fresh blueberries.

If you're not going to use fruit curd immediately after you make it, remember that it's fragile. Made with eggs and butter, curd will only keep about three days refrigerated. Because its flavor is intense and it's a high fat and high calorie treat, we eat curd in small amounts. One solution for storing it is to can it.

In The River Cottage Preserves Handbook, Ms. Corbin teaches how to can jars of curd so that they can be safely kept on a kitchen shelf. Her guideline, however, is that even when properly jarred, fruit curds should be used within 4 weeks (unlike marmalade which can last 2 years), and once a jar is opened, it must be refrigerated.

An alternative to canning is to freeze fruit curd. Make sure the curd is completely cooled, then transfer it to a freezer-safe jar or plastic container. Chill in the refrigerator until it's completely set, and then transfer to the freezer where it can stay for up to a year. Defrost in the refrigerator 24-hours before you plan to use the curd.

So as winter ends and spring pushes to arrive, use some of the last, best citrus to make a couple of pints of lemon curd and store them in the freezer. Then when the best of early summer's strawberries arrive, bake soft, pillow-y biscuits, split them open and pile them high with fresh, sweet berries, and add a soft puddle of lemon curd alongside of the plate.

What a way for the seasons to collide….