This unexpected addition will make buttery confections like shortbreads and shortcakes even more tender and flaky.
“Biscuits should be crumbly, buttery and sweet,” reads a headnote for a cinnamon sugar-spiced shortbread recipe in the Ritz London Cookbook. The recipe includes a peculiar instruction with no explanation: Boil an egg for 10 minutes, remove the yolk, and grate it into the dough.
Molecular biologist and cookbook author Nik Sharma first happened upon this instruction when developing his recipe for Spiced Golden Shortbread Cookies. He decided to do his own research.
As it turns out, adding hard-boiled egg yolks to your biscuit dough is a way to ward off an overworked, tough dough that can be the downfall of a butter-based pastry. When the trick is employed, the pastry shatters and then dissolves in your mouth quickly, tasting like a knob of flaky butter.
Sharma explains that raw eggs are “about 50% water; during boiling, this water participates in the chemical and physical changes inside the egg…and is no longer readily available. As the egg and yolk proteins denature and solidify, they form a mesh and squeeze their water out.” Sharma says that this cooked egg “mesh” becomes kind of like a raincoat preventing water from coming in and drenching your outfit. When the small dustings of cooked yolk are sprinkled throughout the dough, they get in the way of strong, overly chewy gluten formation.
The technique, as it turns out, has been around much longer than the Ritz London Cookbook. New York restaurant owner Larry Forgione learned about this same technique when his friend James Beard shared his mother’s recipe for shortcake as the two were relaxing in Beard’s townhouse. Forgione was so intrigued by the shortcake’s perfectly tender crumb that he put it on the menu at his influential Manhattan restaurant, An American Place, which opened in 1983.
Pastry chef and cookbook author Claudia Fleming first learned about this technique in a professional kitchen from the former pastry chef at Union Square Cafe, where Fleming worked in the late ’80s. In her cookbook, Delectable, the technique comes into play in a recipe for blackberry shortcake. Here, Fleming uses typical shortcake ingredients such as all-purpose flour, baking powder, salt, butter, sugar, turbinado sugar, and heavy cream, but she adds two hard-boiled yolks to her dough mixture. The resulting texture is soft and buttery.
The technique is best used in pastries that you want to break immediately when bitten into. It wouldn’t make sense to use this technique with baked goods like chocolate chip cookies (where you’re trying to accomplish a chew), or sponge cake (where you’re looking for a soft, airy interior). Instead, use it for baked goods that you want to shatter and melt in your mouth, like biscuits, shortcake, shortbread, scones, and dacquoise.
To accomplish the technique, you don’t need to adjust your butter quantities or dry ingredients. All you have to do is boil one or two eggs before baking. Whereas normally when baking with raw eggs, you want to let them come to room temperature before adding them to your mixing bowl, the hard-boiled yolks can be integrated at any temperature. Remove the boiled egg yolk (feel free to snack on the whites) and press it through a fine-mesh sieve directly into your dough before mixing by hand or pulsing it all together in a food processor. You’ll taste the difference that this extra 10 minutes makes in your first bite.
This story originally appeared on Epicurious
