In medium sized, heat proof bowl, add egg yolks. Beat for one minute. Add sugar and beat for another minute. Add fresh lemon juice and lemon zest and stir contents together until combined.

Place bowl over a saucepan of simmering water. The bowl should not be immersed in the water. Cook egg mixture for 10-20 minutes until sauce thickens. Once sauce has thickened, add butter one piece at a time and wait to add another piece of butter until previous one has melted.

Strain mixture through fine-mesh sieve and refrigerate for at least 2-3 hours.

Serve and enjoy!!