In a mixing bowl, beat the eggs and sugar with a whisk until the mixture becomes pale and slightly frothy. This step helps dissolve the sugar and creates a creamy base.
Gradually mix in the lemon juice and zest.
Dissolve the cornstarch in a small amount of water to prevent lumps, then add it to the egg mixture. Stir until well combined.
Cook the Mixture Transfer the mixture to a medium saucepan.
Add the butter, cut into small pieces, to ensure it melts evenly and incorporates smoothly.
Use a wooden spoon or heat-resistant spatula to stir the mixture constantly over low heat. Be patient—it will take 4 to 5 minutes for the curd to thicken.
Once it starts to bubble slightly (the first boil), remove it immediately from the heat to avoid overcooking.
Pour the thickened curd through a fine mesh strainer to remove any lumps or zest for a silky texture.
Allow the curd to cool slightly before transferring it into sterilized glass jars.
Seal the jars and store them in the refrigerator. The lemon curd will keep for about a week, making it perfect for quick breakfasts or desserts!