Whisk the eggs together and set aside. Zest the lemons and then chop the zest as finely as possible. Place all ingredients except the eggs in a glass bowl over a medium size saucepan of simmering water. Medium heat works well for this. When the butter has melted, approximately 10 minutes, and before the mixture is very warm, gradually pour the eggs into the bowl whisking constantly.
Cook, stirring or whisking constantly, until the mixture is thickened to the consistency of pudding. This should take about 15 minutes. Remove from the heat and set the bowl aside to cool. You can strain the curd while it is still warm to remove any lingering bits of zest, if you desire. Once cool, pour into jars and refrigerate. Enjoy!