Add the butter to the Instant Pot. Hit Sauté and Adjust so it’s on the More or High setting. Once melted and bubbling, add the shallots and sauté for 3 Minutes, until translucent.
Add the broth, lemon juice, and dried parsley and stir.
Secure the lid and move the valve to the sealing position. Hit Cancel followed by Manual or Pressure Cook on High Pressure for 3 Minutes. Quick release when done.
Meanwhile, in one bowl, mix together the cornstarch and cold water to form a slurry. In another bowl, whisk together the eggs and cream.
When the lid comes off, give it a stir. Hit Cancel and then Sauté and Adjust to the More or High setting. Once bubbling, immediately stir in the slurry until thickened. Gently stir in the creamy egg mixture followed by the Parmesan and lemon zest. Hit Cancel to turn the pot off.