Prepare a 7-inch springform pan by oiling or buttering the inside of the ring and the bottom.
Pulse the granola in a food processor until it resembles cookie crumbs. Mix with melted butter and press down into the bottom of a 7-inch spring form pan, letting it come up the sides about 1/2 inch.
Place the crust in the oven for 10 minutes to brown, remove and let it cool to room temperature (you can skip this part if you really must, but it adds a nice crunch to the crust).
To make the filling:
Put the egg yolks in the bowl of your stand mixer (or you can use a hand mixer) and whip the them for about 3 minutes, until they turn pale yellow.
Add the condensed milk, lime juice and zest and whip for another couple of minutes. Pour the filling into the springform pan, over your crust.
Cover the pan snugly with tin foil and make a sling out of more foil that you can slip under your pan that you will use to lift it out of the Instant Pot after.
Put a trivet in the bottom of your cooking pot, pour in 1 cup of water and lower your springform pan onto the trivet.
Close up the lid of the Instant Pot. Cook at high pressure for 15 and use 10 minutes natural pressure release when it’s done.
Carefully lift the pan out, using the sling and check to see if it’s done. It will be a bit wiggly in the middle but if it looks like it’s still liquidy, put it back in and cook it for another 5 minutes.
When it’s done, take off the foil lid and let it cool to room temp on a rack then put it in the fridge for a few hours.
Remove the outer ring from the key lime pie.
Make meringue by whipping the egg whites until soft peaks form. Add the sugar and continue to whip until you get stiff peaks.
Pile the meringue on top of the pie and then use a blow torch to brown the top (you can stick under the broiler briefly if you do not have a blow torch but keep an eye on it). Enjoy!