Place all eggs and egg yolks, sugar, lemon zests in a mixing bowl or jug and pour in the lemon juice and whisk to combine.
Place a medium saucepan on the stove over medium heat, pour the mixture and cook, stirring (with a whisk) for few minutes or until the sugar dissolves and the mixture starts to slightly thicken.
Gradually add the butter cubes, stirring (change to a wooden spoon or spatula) continuously until all the butter is melted. Continue to cook, stirring continuously until the mixture is thickened and coats the back of a spoon.
Use a sieve to strain the curd immediately into a mixing bowl or jug, and transfer into the mason jars. Allow it to cool completely, then refrigerate.