When I made preserves for a living, I tried all kinds of curds, from orange to passion fruit, but none of them was ever quite as popular as the good old-fashioned lemon variety. I didn’t think I could improve on it until recently, when I came across an old recipe for an apple-y lemon curd. I tried it out, and I now prefer it even to a classic straight lemon curd. It’s like eating apples and custard: softly sweet, tangy, and quite, quite delicious.

This recipe makes four 8-ounce jars of curd.

Steps

1. Put the chopped apples into a pan with 7 tablespoons of water and the lemon zest. Cook gently until soft and fluffy, then either beat to a purée with a wooden spoon or run through a food mill.
2. Put the lemon juice, butter, sugar, and apple purée into a double boiler or heatproof bowl over a pan of simmering water. As soon as the butter has melted and the mixture is hot and glossy, pour in the eggs through a sieve, then whisk with a balloon whisk.
3. If the fruit purée is too hot when the beaten egg is added, the egg will curdle. One way to guard against this is to check the temperature of the purée with a candy thermometer — it should be no higher than 130 to 140 degrees when the egg is added. If your curd does curdle, take the pan off the heat and whisk vigorously until smooth.
4. Stir the mixture over low heat, scraping down the sides of the bowl every few minutes, until thick and creamy. This will take 9 to 10 minutes; the temperature should reach 180 to 183 degrees on a candy thermometer. Immediately pour into warm, sterilized jars and seal in a boiling-water bath. Use within one month. Once opened, keep in the fridge.