01 -
Choose between indirect cooking in a double boiler or direct cooking in a saucepan. The double boiler minimizes the risk of overcooking, while the direct method requires careful attention and sieving the final product.
02 -
For the chosen method, place sugar and lemon zest in either a heatproof bowl (indirect) or saucepan (direct). Rub zest into sugar using fingertips or the back of a spoon to release lemon oils and enhance flavor.
03 -
Add the egg (and extra yolk if making the rich version) to the sugar mixture. Whisk until smooth, then whisk in lemon juice. Add butter pieces.
04 -
For the indirect method, set the bowl over simmering water in a pot or double boiler. Whisk gently for 7-10 minutes until the mixture thickens to coat the back of a spoon. For direct heat, place saucepan over low heat and stir constantly until thickened, being cautious of curdling.
05 -
Strain hot curd through a sieve into a jar or glass container to remove lumps. Press plastic wrap directly onto the surface and refrigerate until chilled. Cover tightly and store for up to one week in the refrigerator.