Maybe initially that doesn’t sound very enticing. Perhaps it conjures up images of congealed proteins bathed in sour juices. If so, that’s entirely the wrong idea. Think of citrus curd as a smooth, luscious pudding packed with tartness. The bright acidity hits you like a smack of cold air while the generous butter content swaddles your tongue like a warm blanket. Lemon curd is usually what people swoon over, especially when Meyer lemons are in season. But I love limes, and I’m here to tell you that lime curd can do battle with lemon curd any day of the week.
First, a bit about limes. Supermarket limes are typically Persian limes. You can make lime curd with these limes and it will be delicious (in fact, there’s a recipe for curd using regular limes in my cookbook). But I had the great fortune to end up with Mexican limes the other day. Mexico grows two kinds of limes, the ubiquitous Persian limes I just mentioned and a slightly smaller native lime, a variety that is better known as the famous Key lime. Here in the States, when limes are labeled as Mexican limes, you’re usually just getting Mexican-grown Persian limes. But every once in a while, you’ll end up with Mexican-grown Mexican limes. You probably won’t even know it until you leave them on the counter for a while and instead of staying green (or turning brown), they turn yellow like lemons. These limes are more acidic and have a bracing complexity that's hard to resist. They are widely considered to be the very best limes by the people in charge of limes.
You know how crazy people get for Key lime pie, right? Well, this Mexican lime curd is like Key lime pie without the crust. You can just spoon it out of the jar for a spontaneous burst of happiness. It’s also good on biscuits, scones, or coconut macadamia shortbread (WINTERSWEET, p. 92). Mexican limes tend to be larger than Key limes, so it doesn’t take as many or as long to juice them, but the two are interchangeable.
This curd is magical. It is delightful. And it is yours.
I’d recommend organic limes for this recipe since you’ll be using the outer peel. If not, you’ll want to scrub them well. Also, just a note that the finished curd is bright yellow, not green. That’s no mistake. The color is influenced more by the egg yolks than the juice or zest.
1 Tbsp. finely grated lime zest (shiny outer part only, not the bitter white pith)
1 1/4 cup granulated sugar
3 eggs, well beaten
3/4 cup freshly squeezed lime juice from 6 Mexican limes (or ~12 Key limes)
6 Tbsp. unsalted butter
Pinch of salt
Place a large bowl half-full of ice water near the stove. Next to that, set a wire-mesh strainer nested inside a medium metal bowl.
In a medium saucepan, rub the lime zest into the sugar with your fingers until moist and fragrant. Whisk in the beaten eggs and lime juice. Add the butter and salt, and set the pot over medium-low heat. Cook, stirring constantly with a wooden spoon, until the butter melts and the mixture thickens, 5 to 10 minutes. Do not boil. Wait for when the mixture thickens to the consistency of a loose pudding. It should coat the back of a spoon, leaving a distinctive track when you run your finger through it. At this point, remove the pot from the heat.
Set the bowl with the strainer inside the ice bath, and quickly pour the curd through the strainer into the bowl, using a rubber scraper to force the curd through the sieve. (The ice bath halts the cooking and the strainer is insurance to remove any overcooked egg proteins that may arise. Be sure to scrape as much of the curd as possible off the underside of the strainer.)
Let the curd cool for a half hour before pouring it into small jars. The curd will thicken further and the flavor will intensify as it chills. Keep refrigerated for up to 2 weeks.