Treat Closet
August 26, 2014
As a person who ADORES key lime pie with meringue topping, I have tinkered with this problem for years and have discovered many things through similar exasperating failures.
Meringue can be tricky, but there are a couple of great secrets: When you beat your egg whites, everything needs to be squeaky clean, no trace of oil, yolk, any kind of fat or they won’t fluff up fully. Cold eggs separate easily, room temp whites beat more easily. For 5 egg whites, add 2 Tbsp powdered egg white (“Just Whites”) to absorb excess moisture. Beat the whites with a large balloon whisk for greatest height. Beat until they barely start to froth up then add 1/2 tsp cream of tartar, a pinch of salt and a tsp of caster sugar (finely ground sugar.) You can grind your own in a coffee grinder as long as it is squeaky clean and free of coffee oils. The finer the sugar, the better it dissolves, avoiding those pesky undissolved beads of sweet liquid on top of your finished meringue pie. Adding these ingredients before you beat further prevents that awful separation of fluff and runny stuff that occurs when you overbeat whites. Now your mixture is stabilized and you can beat it like crazy and it won’t easily overbeat!!! Yay!
Now add the rest of your caster sugar one Tbsp at a time (I use 9 Tbsp in total) and ideally let it sit while you do other things, so the sugar is fully dissolved.
Prebake your pie crust 7 min at 325F and then add your lemon (or key lime) filling and bake that for 10 min so it’s hot before you spread your meringue on it. (Rebeat the meringue just before spreading for greatest height). You see, the runniness you’re experiencing is the uncooked white running down and sitting on top of the cold filling and never fully cooking. The hot filling prevents this from happening.
I like the cornstarch GEL trick (1 Tbsp cornstarch to 1/3 cup cold water, cooked till it loses its chalky taste and starts to look clear), and I add 1 Tbsp of it to my FILLING, and 1 Tbsp of it to a tiny amount of meringue in a separate bowl, get it really well-blended with no lumps, then spread that thinly over the hot filling. It seals the two layers that way, but doesn’t affect the texture/fluffiness of the finished meringue.
Bake the whole thing for 20 min. more, then turn off the oven and open the door 1/4 of the way and let it come down in temp. for 10 min. Remove from oven and then let it come to room temp, then refrigerate fully before slicing.
The ideal outcome is a silky textured flan-like filling and a high, non-shrinking white with a crisp crust. It might seep a little syrup after cutting and refrigerating a day or 2, but just fold a paper towel and place it in the pan to absorb this and your crust won’t get soggy.
