Here is a silky smooth, sweet and tangy treat that makes a terrific gift, especially around the winter holidays when citrus is in season. It is fantastic as a filling between cake layers, as well as spooned over fresh fruit. A favorite way to enjoy lemon curd is to serve a dollop of it on top of gingersnap cookies.
- Grate the lemon zest off of two of the lemons.
- Alternatively, use a vegetable peeler to strip off just the yellow part of the zest, leaving the bitter white parts behind. Pulse these strips in a food processor until they are very finely minced.
- Cut the zested lemons in half and squeeze out and strain the juice. Measure the juice. You need 1/2 cup to make the lemon curd. If necessary, add the juice from an additional lemon. Tip: Save the seeds and the white parts of the lemon peels to make citrus pectin for future jams and jellies.
- Add an inch or two of water to the bottom part of a double boiler, or improvise a double boiler by placing a heat-proof bowl over the top of a pot (put an inch or two of water in the pot). Bring the water to a boil over medium heat.
- In the heat-proof bowl or top part of the double boiler, whisk together the 2 eggs plus the third egg yolk. Add the sugar and the butter (in small chunks), along with the lemon juice and zest.
- Whisk until the sugar is completely dissolved and the butter completely melted. Switch from a whisk to a spoon and stir, very frequently, until the mixture begins to thicken, about 10 minutes.
- Meanwhile, sterilize the jars.
- From the moment the curd begins to thicken until the end you're on duty: stir nonstop until the curd is thick enough to coat the back of a spoon. If you're not sure, a backup test is to put 1/2 teaspoon of the curd on a cool plate. Within a minute it should set up to a thick consistency somewhere between a custard and a pudding.
Tips: The stirring constantly is important: if you don't you will end up with small pieces of scrambled egg in your lemon curd. Also, if you've never made fruit curds before, it's helpful to know that the curd won't be fully thickened to the soft pudding consistency you want while it's still hot.
- Spoon the curd into the sterilized jars leaving between 1/4 and 1/2-inch head space. Secure the lids.
Unless the jars are sealed by processing, fruit curds will only keep in the refrigerator for 1 to 2 weeks. For longer storage, process 1/4 or 1/2-pint jars of lemon curd in a boiling water bath for 15 minutes. Once processed, jars of lemon curd will keep in the refrigerator for 3 months until they are opened (after opening, they will only last 1 - 2 weeks). The surface of curd in sealed jars may darken slightly if kept longer than a month, but that is only an aesthetic concern, not a health hazard.
Experienced canners may be raising an eyebrow in query: Do you really need to refrigerate the sealed jars even though you've processed in a boiling water bath? Yes, with fruit curds, you do.
Lemon curd can also be frozen for up to 1 year.