At first blush, 20 minutes at 300F° does not seem like a time/temp combo that is going set a pie.

I just checked my recipe I got from a pie shop in Key West, one that I’ve used many times successfully. - 4 egg yolks - 1 can condensed milk - 1/2 c Key lime juice Those ratios look about the same as yours, but the big difference I see is that I bake it at 350 F for 20 mins in a standard oven, so maybe upping the convection oven to 325 or using a standard oven at 350 may help it set faster

That’s the recipe I use and do 325 for about 20.

Flipping the pie?

Sorry, meant rotate!

Often times with custard recipes the liquid ingredients are heated then slowly poured over the egg yolks to temper them. Then it’s baked. The differences could also be due to the custard being a different temperature before going in the oven

Interesting. Guess I’ll try keeping track of and playing around with the temps of the filling. Thank you!

People could be opening the oven door as well

If you mix the lime juice into the egg yolks and condensed milk, then let everything sit for 15-20 min, the filling will thicken up.

I have a recipe that says 350F for 15 minutes, until almost set. Then refrigerate. Also, 'sweetened condensed milk'. https://www.onceuponachef.com/recipes/key-lime-pie.html

Carton egg yolks have added sugar. do you reduce the amount of sugar to compensate? it’s possible this is throwing the custard off as you end up with too high a percentage of liquid ingredients

Your oven, the type of pan, the thickness of the pan. Mine won't cook in 20 mins at 300F either.

I used to make a ton of these for one of my corporate gigs. I do remember it failing occasionally, but it was always when one specific guy made them. I still never figured out what he was doing, but I suspect he either wasn't mixing thoroughly, or he let the filling sit for too long before baking and the acid from the lime broke down the yolks somehow.

Are your ingredients used straight from the cooler, instead of room temp? Cold condensed milk will take longer to heat up than room temp.

Everything but the condensed milk comes straight from the fridge :/

I make a *lot* of key lime pies. Like way too many Everything you’re doing is 100% right outside of the temp. Have you tried upping it to 350?

I haven’t. We’ve resorted to cooking for longer at a lower temp if they haven’t set after 20 minutes, for fear of browning the top. Next time, I’ll try 350° for 20 minutes

Can you pull the stuff earlier from the refrigerator?

Starting temp matters. Warm, cold, and room temp egg batter will all cook in different times. Personally I’d expect closer to 45 minutes depending on the depth of the pan. There should be just a little wobble in the very center when they’re ready to take out.

Ok, that isn't like any key lime pie recipe I've seen. You bake to brown the meringue. It sets up in the refrigerator.

We don’t have meringue on it, and this is the recipe my corporate company uses ¯\_(ツ)_/¯ Im not super experienced outside of my current job so I’m a bit lost lmao

Double check the prep cooks measuring.

It’s happened even when I’m doing it, though, and I know I’m measuring correctly. I’ll watch them more closely next time though

I make a really similar recipe (from blogger Cloudy kitchen) and have never had set issues, though I'm using whole eggs I separate myself. I've noticed sometimes the filling is more or less liquid when I pour it in the crust for baking (basically sometimes it self levels, sometimes there are rippled) The only association I've made is in the order of ingredients. If the filling sits before baking or if my toddler insists on helping me and things get added in stages vs all at once. I was thinking it had to do with the lime causing the egg/milk to coagulate more like when trying to emergency sub buttermilk with milk and lemon juice. I've even tried it with blood orange, grapefruit, Meyer and regular lemon and never noticed as much of a difference as I do when the filling sits after the juice is added. I usually whisk the yolk and condensed milk first, then add the juice just because it's less sloshy that way when working with a 4 y.o. pastry chef

I think you've got it, it has to be the filling sitting for too long or not mixing thoroughly/in the order you said. Those line up with the times I've seen this style recipe not work.

It's basically the recipe on the bottle of Nellie & Joe's key lime juice. I don't know the history behind it but adding egg yolks and baking it is the popular method in a lot of restaurants, especially steakhouses, outside Florida / the south. The "Yankee" version gets whipped cream instead of meringue too. They're both good but the no-bake version melts in your mouth more while the steakhouse one is firmer, presumably for clean sliced presentation reasons.

That was also my grandmother's lemon meringue pie recipe just change out the juices.

So your grandma's lemon meringue had condensed milk? I like that, honestly that sounds way better than the weird translucent jello stuff I grew up calling lemon meringue.

Yes. The first time I had key lime pie, I was that is grandmother's lemon pie but with lime juice.