1-First Step: Set up your double boiler Fill the bottom of a double boiler with 1 to 2 inches of water and bring it to a simmer over high heat. After it starts simmering, reduce the heat to low so the water stays gentle. If you do not have a double boiler, place a heatproof glass bowl over a saucepan of simmering water. This setup helps the curd cook slowly and keeps the eggs from scrambling.

2-Second Step: Mix the base ingredients In the top pot or bowl, whisk together the egg yolks, sugar, lemon zest, lemon juice, and salt. Keep whisking constantly as the mixture warms. This part matters because the sugar needs to dissolve and the eggs need to cook evenly. You want everything smooth before the thickening starts.

3-Third Step: Cook until thick Keep whisking over the simmering water until the mixture thickens to a hollandaise sauce texture. This usually takes about 10 minutes, and the temperature should reach 170°F. If it is not thickening, raise the heat a little while still whisking. The mixture should coat the back of a spoon and look glossy, not lumpy. This is the moment where patience pays off.

4-Fourth Step: Add the butter Remove the pot from the heat once the curd reaches the right thickness. Add the softened butter pieces and whisk until completely melted and blended. The butter gives the curd its smooth finish and rich taste. If you want an extra silky texture, keep whisking until the surface looks shiny and even.

5-Fifth Step: Strain if needed If you notice any tiny bits of cooked egg, strain the curd through a fine-mesh sieve into a clean bowl or jar. This step is optional, but it is a smart move if you want the smoothest result. A quick strain can rescue a slightly grainy batch and make the texture feel more luxurious.

6-Final Step: Chill and set Pour the Lemon Curd into a jar or bowl. Cover the surface directly with plastic wrap so a skin does not form while it cools. Refrigerate it until set, which usually takes about 1 hour and 15 minutes total including cooling. Once chilled, it should be thick enough to spoon, spread, or swirl into your favorite treats.