Good morning, students, and welcome to the first day of Egg Whites 101.
Didn’t realize you’d gone back to school? Don’t worry, I’ll give you plenty of warning before the midterm. Plus, this is the kind of class with lots of sugar and even some chocolate, which is the best kind. Here’s the deal: instead of me reading up on some aspect of food chemistry and then feeling the need to tell you ALL OF THE THINGS about, you know, gluten or sugar or something in one fell swoop, we’ll stick to one topic for a month or so and tackle one piece of the science at a time. And you’ll still get a new recipe with each post! Have an idea for a future subject? Let me know!
First up, egg whites. Mostly because they’re just really really cool. I love how Harold McGee puts it: “Thanks to egg whites we’re able to harvest the air” (On Food and Cooking, 100). As a devotee of eggs for breakfast, either poached or fried, I mostly encounter egg whites as the firm and sometimes crispy counterpoint to the rich runniness of yolk. On my breakfast plate, the yolk is the clear winner, but the white definitely holds its own in the sweet treats department. Its defining feature is the ability to be whipped into stable foams, which give us pillowy meringue pies, rich souffles, fluffy pancakes, and melt-in-your-mouth meringue cookies. For something that’s 90% water, that’s pretty amazing.
Basically, a foam is just air pockets suspended in a liquid of some sort. Aficionados of cappuccinos or lattes love the familiar sight of milk foam on top of espresso, and meringue uses the same principles. Egg whites yield a much more stable product, though, because of the way their proteins interact with each other and with the air. The proteins in an untouched egg white exist mostly as compact, intricately folded balls with little interaction between them, while a foam relies on these same proteins as long, unraveled threads that tangle together and trap air inside their network. Think of neatly coiled balls of yarn versus the knotted mess that a pet or a small child can make out of a knitter’s closet. The former is very self-contained, while the yarn web will ensnare unwary toys and toes, like the air bubbles in whipped egg whites.
As your whisk whips through the unsuspecting egg whites, it pulls the folded proteins out of their compact shapes. They slowly enlongate and begin to interact with other lengthening proteins, forming bonds that connect the separate strands and build on an emerging network. The action of the whisk continues to introduce new air bubbles and unfold proteins, strengthening the foam from bubble-bath delicate to a stiff meringue that holds its shape.
Chocolate hazelnut meringues
These light, crispy cookies still pack a strong chocolate punch. Delicately crunchy, they melt in your mouth for a smooth burst of flavor. Grinding the sugar may seem like an unnecessary extra step, but it makes it dissolve more easily into the egg whites and gives you a better finished product.
Yield: about 60 1-inch cookies
3/4 c. plus 1 T. sugar
3 egg whites
1/4 t. cream of tartar
1/4 t. salt
3 T. cocoa powder
1 t. hazelnut extract (available in the baking section of most grocery stores)
Chocolate chips and toasted hazelnuts, optional
Preheat the oven to 200 degrees F. Line a baking sheet with parchment paper.
Grind the sugar in a food processor for about one minute. Set aside.
Using an stand mixer or electric hand mixer, beat the egg whites until bubbly. Add the cream of tartar and salt, then gradually add the sugar while whipping. Beat the egg white mixture until it is thick, shiny, and holds its shape on the beaters.
Add in the cocoa powder and hazelnut extract, and mix until combined.
Transfer the meringue to a pastry bag with a large plain or star top. Pipe the cookies onto the prepared baking sheet and bake for 2 hours. Turn the oven off and leave the cookies in the cooling oven to finish cooking.
If you want to jazz up your cookies, dip them in melted chocolate chips and roll in crushed hazelnut.