Zest the lemons so that you have 2 teaspoons of fresh zest and then juice them to yield ½-cup of fresh juice. Strain the juice to remove any seeds.
In a heavy saucepan, melt butter over medium heat.
While the butter is melting, whisk together lemon juice and eggs in a cup with a spout. A 2-cup liquid measuring cup works well.
Add the sugar to the egg and lemon juice mixture and whisk well to partially dissolve the sugar and combine all of the ingredients.
Whisking the contents of the saucepan vigorously, pour a thin stream of the egg mixture slowly into the melted butter. Once all of the egg mixture has been added, switch to a wooden spoon for stirring. Continue to stir over medium heat until the curd coats the back of the spoon. Remove the pan from the heat.
Pour the cooked curd through a mesh strainer in to a bowl. Stir the zest into the curd. Cover with plastic wrap and chill for one hour, tightly covered.
Nutrition facts are sometimes provided below and are calculated using an online calculator. With specific brands of ingredients and additions, omissions, or substitutions the nutrition facts may change. We encourage you to use your own nutrition facts calculator to obtain the most accurate nutrition facts for your meal.