Step 1

In a large microwave-safe bowl, whisk together the sugar, eggs, egg yolks, lemon juice and salt (1/8 teaspoon if using unsalted butter) until smooth. Add butter cubes. Microwave on high power for 45 seconds. Remove and stir vigorously with a whisk.

Step 2

Continue to cook 45-second intervals, stirring after each interval. It will take 4-7 minutes, depending on the power of your microwave. Lemon curd is done cooking when it coats the back of a metal spoon. You can also check it with an instant thermometer. It’s done when it reaches 175˚F.

Step 3

Remove from the microwave and whisk well. Add lemon zest and stir. Allow the curd to cool to room temperature. It will thicken as it cools. Cover and store in the refrigerator.