Pour 1 cup of water into the insert of your Instant Pot. Place a colander inside the insert and place the eggs in one layer in the colander. Make sure if your colander has handles that they are fastened together otherwise they can interfere with the sealing of the Instant Pot. Place the lid on the Instant Pot, making sure the valve on the top is set to Sealing.
Plug in your Instant Pot, then press the Manual button. Use the plus and minus buttons to adjust the time to 7 minutes, then let it get cooking.
Once the timer goes off, release the pressure by moving the top valve to Release - do this carefully as you don’t want to get shot in the hand with the hot steam! While the steam releases, make an ice bath for the eggs. Fill a medium size bowl about two-thirds of the way up with cold water and place two handfuls of ice cubes in there as well.
When the pressure has been fully released, remove the lid and (carefully, using a hot pad or towel if necessary) lift out the colander with the eggs. Gently pour the eggs into the ice bath and let cool for 5 to 7 minutes (until they’re cool to the touch).
Next up is to peel the eggs. Start by gently tapping on each end, then rolling gently but firm enough to crack the shell. Peel the pieces of shell of with your fingers and throw them away. You may need to rinse the eggs quickly in water to get any small pieces of shell off.
Cut the eggs in half length-wise with a small sharp knife either in your hand (being VERY careful not to cut yourself or with a cutting board. Put the yolk pieces into a small bowl. Most of the pieces can be popped out with your fingers, however some may need to be dug out a bit with the knife. Just be careful nut to tear the egg white. Set the egg whites aside on a dish or paper towel.
Mash up the egg yolks with a fork until no large pieces remain, then measure out and add in the mayo, mustard, kosher salt, and lemon juice. Combine everything together until the mixture is smooth - you can do this either with a fork, a large spoon, or to really get things smooth you may want to use an electric beater or whisk.
Take out a quart-sized plastic bag and spoon the smooth egg yolk mixture into it, toward one corner. Once the mixture is all in the bag, use scissors to cut a small amount of the corner piece off, enough to leave a whole between a quarter and half inch wide.
Squeeze the mixture down toward the hole with your hands, the squeeze a small amount (about a tablespoon) into each of the egg white halves. You can wiggle the bag back and forth to make a pattern or just squeeze directly into the cup of the egg white. Garnish with a dash of paprika or some chopped dill fronds if desired.