Add berries, sugar, and lemon juice to pressure cooker.
Close and lock lid, set pressure cooker to "steam/veggies", adjust time to 1 minute, and press "start/stop".
When done, natural release for 20 minutes, then quick release to make sure all pressure has been released before opening lid.
Carefully open lid and remove berries and strain. Using a spatula, push berries through strainer to remove seeds.
In a bowl, whisk yolks. Slowly whisk in hot raspberries. Add mixture to cooker.
Set to "sear", adjust time to 10 minutes, and press "start/stop". Bring mixture to a boil. Turn cooker off and stir in butter. Pour mixture into storage containers and cool to room temperature. Refrigerate until ready to serve.
