Most of the recipes I have tried, say to include 1 1/2 cups of sugar and sometimes they suggest more.  I find that lemon curd is often too sweet and it is much better if it is a bit tart.  I do it as follows!

Four lemons, (approximately 1 cup of juice, give or take.  it you only get 3/4 of a cup that is fine too)

1/2 cup butter at room temperature

1 cup white sugar

4 large eggs

1/4 tsp. kosher salt

Remove the zest from the lemons.  Only the yellow part and avoid the white pith.    I use a microplane and grate them onto a piece of waxed paper.  The zest gives the lemon curd a rich lemon flavour.

Squeeze lemons and set aside.

I squeeze my lemons into a measuring cup so I can see how much I am getting.  Then I use a small sieve when transferring the juice from the measuring cup to the mixing bowl.

In a medium saucepan, melt butter, lemon zest, lemon and sugar on low heat stirring constantly. As soon as the butter is melted, remove the pan from the heat and allow to cool for five minutes. Add salt!

crack four eggs into a bowl or measuring cup and whisk lightly. put four TBLSP liquid mixture into the whisked eggs to temper. slowly pour egg mixture into slightly warm lemon mixture. place saucepan back on burner. On medium heat, whisk constantly until mixture thickens.

 This will take approximately 10 minutes.  Be patient and you will be rewarded with a thick lemon mixture.  Transfer to a glass bowl.  It continues to thicken as it cools.  Cover with plastic wrap so that it rests right on top of the curd.  Once it has come to almost room temperature place  the bowl in the fridge until you are ready to use it.

This will make approximately three cups of curd and can be used in recipes or served on it’s own.