The curd is done when the temperature reaches 170˚F and you can run your finger cleanly through the test sample on the back of the spoon. The mixture will still be a little runny but will firm up upon cooling.
Lemon curd is one of those things that I always like to have in my refrigerator. It has saved me more than once when I've had to rustle up a last minute dessert or had an unexpected guest stop by at tea time. I love how lemon curd is tart (at least the way I make it!) and yet rich and smooth. Honestly, I could just eat spoonfuls of it straight from the jar!
Classically, lemon curd is served with tea, where it is spread on scones, biscuits, and shortbread. It also makes a nice filling for cakes and tarts, especially when topped with fresh fruit. You can sandwich it between cookies, swirl it into ice cream or yogurt, fill chocolates, choux pastry or crêpes, and slather it on poundcake and pancakes.
I like my lemon curd to be very tart, so the amount of sugar called for in this recipe is quite low compared to some. You can increase the sugar to as much as 1 1/2 cups if you like it sweeter. I also like to mix everything in a food processor as the sharp blade really cuts the lemon rind into the sugar, releasing all the flavorful oils.
Of course, lemon isn't the only flavor of curd. Try experimenting with limes, meyer lemons, grapefruits, and blood oranges. Some of these fruits are sweeter than others, so adjust your sugar up or down accordingly. Jars of lemon curd make very nice gifts, so feel free to experiment and take advantage of the citrus season while it's still here!
How To Make Lemon Curd
Makes about 1 cup
What You Need
3 or 4 lemons
3/4 cup sugar
8 tablespoons unsalted butter (1 stick), cut into pieces
5 large egg yolks
1/4 teaspoon salt
Food processor (see Recipe Notes)
Small sauce pan (1- to 2-quarts)
Instant-read or candy thermometer (optional)
Jar for storage
1. Peel and juice the lemons. Peel 3 of the lemons, taking as little of the bitter white pith as possible. Cut all the lemons in half, juice them, and measure out 1/2 cup of juice. Save any leftover juice for another use.
2. Mix everything in the food processor. Combine the sugar and lemon peels in the bowl of a food processor and process until the peels are ground very fine, about 30 seconds. Add the butter, egg yolks, lemon juice and salt to the bowl. Pulse a few times and then process for 15 seconds or so to incorporate everything. The mixture will looked curdled but that's OK at this point. (See Recipe Notes, below, for making lemon curd without a food processor.)
3. Prepare the strainer. Place the stainer over the bowl so it is ready to go when your curd is done cooking.
4. Cook the lemon mixture. Pour mixture into a small saucepan and place over very low heat. Stir frequently, using a heat-proof spatula. Do not leave the mixture unattended as it is very easy for it to overcook and curdle.
Cook until the mixture begins to thicken, 12-15 minutes. If you are using a thermometer, cook the curd to 170˚F. You can also test the curd by coating the back of a spoon with the curd and running a finger through it. It should leave a clear, distinct path.
4. Strain and store. Pour the curd through a strainer to catch any peel and coagulated egg. If your strainer fits over your storage jar, you can simply strain it right into the jar. Otherwise, strain it into a bowl and then pour it into a jar. Allow to cool to room temperature, then seal the jar and store in your refrigerator. It will keep for a few weeks, if it lasts that long!
• If you don't want to use a food processor, remove the lemon peel with a zester or rasp and incorporate all the ingredients into a bowl by hand. You can also use a stand mixer.
• Lemon curd can also be stored in the freezer for several months.