Why You Should Add Hard-Boiled Egg To Your Biscuit Dough
The perfect biscuit is delicate, flakey, and fluffy all thanks to the interplay of fat and flour. Unfortunately, this flakey, buttery outcome faces a lot of obstacles. If you've ever attempted to make a batch of biscuits, you're likely familiar with how finicky the process is. If the proportion of flour and fat is even slightly off, the consistency of your biscuits will miss the mark; too much flour results in dry, crumbly biscuits, while uneven fat distribution or overworked dough results in tough or dense biscuits. While there are plenty of tips to achieve the desired fluffy, melt-in-your-mouth crumb, adding a hard-boiled egg yolk to the dough is probably one you haven't tried.
Boiled egg yolk is essentially an extra dose of pure fat that's also been rid of its water content that'll easily disintegrate and distribute throughout the flour to create a buffer against gluten formation. Gluten is the compound made by the reaction of two key proteins in wheat flour that gives boule bread and pizza dough its chewiness. With biscuits, however, the goal is to avoid this chewiness. So, by adding hard-boiled egg yolk to a biscuit recipe, you'll thwart the formation of gluten, thereby resulting in a buttery, flakey crumb that'll dissolve in your mouth. The hard-boiled egg yolk hack is actually a longstanding practice for other pastries like shortbread cookies, shortcakes, and scones that also possess the same crumbly, buttery, and tender nature.
How to incorporate hard-boiled egg yolk into biscuit dough
Adding hard-boiled egg yolk to biscuit dough doesn't require any ingredient swaps or proportion changes. You can thus add them to your favorite biscuit recipe as a supplemental ingredient. For a standard batch of biscuits, you can use one or two hard-boiled egg yolks. You'll want to make sure you hard boil your eggs, as runny or jammy eggs aren't ideal for distribution in the flour.
You can use hard-boiled egg yolks fresh out of the pot or you can wait for them to cool completely. To add them to the batter, you'll run them through a mesh sieve or grate them along with cold butter into a bowl or mixer with the rest of your ingredients. Of course, all the same tips for a flakey crumb still apply, like using frozen, grated butter, and barely working the ingredients with your hands or a fork to form loose and crumbly dough.
Similar to other yolk-heavy types of bread like brioche or challah, the addition of egg yolks to your biscuit dough may give your biscuits a yellow hue. Once you taste the buttery, perfectly executed crumb, yellow coloring will be a welcome visual cue.