Infuse the sugar with lemon zest: In a medium heatproof bowl, combine the sugar and lemon zest. Use your fingertips to rub the zest into the sugar until fragrant and slightly moist. This step helps release the natural lemon oils for extra flavor.
Whisk the base: Add the egg yolks and whole eggs to the bowl and whisk until well combined and slightly thickened. Then whisk in the lemon juice until smooth.
Cook the curd: Place the bowl over a saucepan with gently simmering water (double boiler method). Cook the mixture, whisking constantly, until it thickens enough to coat the back of a spoon, about 8–10 minutes, or until it reaches 170°F (77°C). Don’t let it boil, or the eggs may curdle.
Add the butter: Remove the bowl from heat and immediately whisk in the butter, until completely melted and the curd is glossy and smooth.
Strain for silkiness: Pour the curd through a fine-mesh sieve into a clean bowl or jar to remove any bits of cooked egg or zest. This ensures a perfectly smooth texture.
Cool and chill: Press a piece of plastic wrap directly onto the surface to prevent a skin from forming. Let cool to room temperature, then refrigerate for at least 2 hours before using. The curd will continue to thicken as it cools.
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Notes
Eggs vs. Yolks: Using both whole eggs and yolks gives this curd a balance of richness and lightness. For an ultra-creamy, custard-like texture, use 4 yolks instead of 2 yolks + 2 eggs.
Use fresh lemons: Freshly squeezed lemon juice and zest make a big difference in flavor and aroma. Avoid bottled juice, it lacks the brightness and natural oils of fresh lemons.
Infuse the sugar properly: Rubbing the lemon zest into the sugar helps release essential oils, giving your curd a stronger, more aromatic lemon flavor. Don’t skip this step!
How to Know It’s Ready: The curd should coat the back of a spoon — if you run your finger across it, the line should stay clean. Avoid overcooking; curd that gets too hot may curdle.
Strain for smoothness: Straining removes any bits of cooked egg or zest, resulting in a silky texture worthy of a bakery.
Butter quality matters: Use unsalted butter for better control of flavor. Add it at the end to create a glossy, rich finish.
Serving size note: This recipe makes about 1½ cups (360ml) of lemon curd, roughly 8 servings (2–3 tablespoons each). Nutritional information is calculated for the entire batch, so adjust based on your portion size if needed
Storage: Store in an airtight jar in the refrigerator for up to 1 week, or freeze for up to 3 months. Thaw in the fridge overnight before using.
Leftover egg whites: Don’t throw away your leftover egg whites! You can use them in other recipes like meringues, macarons, or fluffy omelets, see my guide on What to Do with Leftover Egg Whites.