The world of meringues is a wide one. Broadly speaking it’s divided into two categories: cooked meringues and uncooked meringues. However within those two groups there’s a lot of variation. Meringues can be mildly sweet or intensely sweet. They can be light and frothy or dense and marshmallow-y. They can be baked to crispness, browned in the oven (or with a blowtorch) or eaten as they are.
An American pie meringue is an uncooked, medium-sweet, light and frothy meringue that is also gently baked. This makes it a different animal compared to the denser, creamier cooked meringues that typically adorn European-style lemon tarts, even though the presentation looks very similar. American pie meringue is a sweet froth that makes a lovely counterpoint to a dense citrus curd, as it heightens the fresh feeling you get when you put a bit of both in your mouth.
A common question in regard to American pie meringue is: if the idea is freshness and lightness, why does it need to be baked at all? The answer is that unlike denser, more sugar-intensive meringues, American pie meringue it will lose volume and weep moisture if the egg proteins in it aren’t coagulated just a little bit. The bubbles inside it are large and not heavily reinforced with sugar syrup. It takes a little lightly cooked (slightly clumped up) egg protein to shore them up. Take that idea too far of course and those same proteins clench too tightly, squeeze out moisture and, well, see below.
Still it’s all worth it to my mind, since there’s nothing better as a closer to summer meal than the delicate texture of a good meringue pie.