Grease the baking cups with the butter, making sure to coat all of the ridges. They’ll unmold easiest when the cups are well-coated. Place the greased baking cups on top of the Pressure Cooker Bakeware Sling.
Sprinkle the grated cheese and green onions into the baking cups.
Blend the eggs and Laughing Cow cheese in a blender on medium-low speed for about 30 seconds, until thoroughly combined with no flecks of cheese remaining.
Pour even amount of egg mixture into the cups. It should go just up to where the cups turn from shiny to dull (that’s the max fill line).
Pour 1 cup of water into the Instant Pot.
Holding the handles of the pressure cooker sling, slowly lower it into the pot, taking care not to tip over the baking cups. Clasp the ends of the sling together.
Secure the lid in its Sealing position, then select the Pressure Cook setting for 8 minutes at low pressure. (It will take about 7 minutes for the pot to come to pressure before the cooking program begins.)
When the cooking program ends, let the pressure release naturally for 5 minutes, then move the Pressure Release to Venting to release the remaining steam.
Open the pot. The egg muffins will have puffed up quite a bit, but don’t worry -- they will settle back into the baking cups as they cool. Wearing heat-resistant mitts, unclasp the sling and lift it out onto the counter.
Let the egg muffins cool for a couple minutes, until they are comfortable to handle. Pull the sides of the baking cups away from the muffins to unmold them, then serve warm. They’ll also keep, refrigerated, for up to 3 days.