With a mixer, cream together the butter and sugar until fluffy.
Add in the lemon zest, eggs and egg yolks and mix until smooth.
Pour in the lemon juice and mix until combined.
Pour the mixture into two pint jars and cover with foil (or very loosely with canning lids, just until the lids catch)
Add one cup of water to the bottom of the pot and place the trivet inside. Place the jars on the trivet and close/lock the lid. Turn the steam release valve to closed and press Steam. (high pressure, 10 minutes.) Press Start/Stop.
When the cooking cycle has ended allow natural pressure release for 10 minutes and then release any remaining pressure. Remove from the pot and open up the jars to stir and cool.
Stir each jar well with a whisk until the mixture comes together and is smooth and creamy. Allow to cool 10-20 minutes at room temperature and cover and refrigerate.
Chill for at least 4 hours. It will thicken and the flavors will sharpen as it cools.
Serve on top of cheesecake, inside pastries or enjoy with a spoon!