The Surprising, Unorthodox Ingredient for Loftier, Fluffier Biscuits

I am neither a Southerner nor a biscuit analyst, yet this Instagram from Tom Hirschfeld gave even me pause: an egg in biscuit dough?! Is this proper?

(Spoiler alert: I couldn't determine propriety, but I did test the effect of an egg. Click here to skip to those results.)

For Tom's ideal biscuits—high risers that fan apart in layers (as opposed to crumbling in a soft, squat tenderness)—he adds an egg to the dough and bakes at a lower temperature (375° F).

I couldn't find much precedent for the addition of an egg: not in Alton Brown's biscuits, nor in Edna Lewis', Deb Perelman's, Saveur's, ChefSteps', Bon Appétit's, King Arthur Flour's, Southern Living's, Mark Bittman's, Blackberry Farm's, Beth Kirby's...

I did find buttermilk biscuits that incorporated egg, however, from Ina Garten and Serious Eats. And while Ina doesn't give much explanation for her egg inclusion, Serious Eats' Marissa Sertich Velie cites several reasons. Eggs, Velie explains,...

• Create a richer flavor
• Work in tandem with the baking powder to leaven the biscuits for extra height
• Tenderize (due to the added fat in the yolk)
• Contribute to a more golden-brown color (the additional protein contributes to the Maillard reaction)

The comments section on the Serious Eats article reveal some befuddlement—"And eggs? Whoever heard of such non-sense..."—but also some gratitude—"I found the egg in the biscuit batter odd at first until it was the only way my biscuits turned out right."

There was only one way to determine right from wrong (just kidding: to see how much of a difference the addition of one measly egg could really make)—a biscuit test:

I doubled the same biscuit recipe (I chose A Cozy Kitchen's Flaky, Awesome, Perfect Buttermilk Biscuits for its simplicity and because it calls for an egg to be whisked into the buttermilk) and baked at three different temperatures 375°, 400°, and 425° F. (A couple relevant notes: I had to add an additional tablespoon or two of buttermilk to get the non-egg dough to come together; I brushed every biscuit with a mixture of egg and buttermilk; and I used the same size biscuit cutter for every cut-out.)

Thanks to the June Oven, a smart oven with a camera inside that connects to a mobile app, I could spy on my biscuits as they baked (and then share those videos here).

Here's how the biscuit test broke down:

Across all temperatures, the biscuits made with the egg were decidedly taller (and, in my view, more beautiful). They were less fragile, with a doughier moistness that the all-butter biscuits were missing.

But the all-butter biscuits had a deeper, more purely buttery flavor, uninhibited by the addition of egg, and required less chewing (the descriptor "meltingly tender," while cringeworthy, is not inappropriate here).

Kristen Miglore, Creative Director and my accomplice in biscuit-tasting, asked a fair question: Are there certain instances in which you'd want a taller, sturdier, but maybe a bit less flavorful, biscuit? Why, yes! Perhaps if you're using that biscuit for a sandwich (and want to be able to cut it in half without it crumbling), or covering it with heavy gravy, or making it into a biscuit Benedict, the lofty flakiness will be of great benefit.

The final verdict: If you're looking for a fall-apart, no-chewing-required softness and a pronounceable butter-flavor, you might do best omitting the egg. If you want a biscuit with impressive looks at great height, whisk an egg into the milk mixture and be on your way.

As for the color, the biscuits were all surprisingly yellow inside and out, even those that were made without the addition of egg. I wouldn't have been able to judge a biscuit egg or no egg by color alone (even if the height and flavor would be dead giveaways).

The biscuits that were by far the most golden-brown were those baked at the highest temperature 425° F. Other than that, I had a hard time discerning any significant differences that the baking temperature made: Perhaps those baked at 375° F were a bit drier, as they took an additional five minutes in the oven longer? (Hard to say.) And the biscuits at 425° F had, I think, a discernibly crispier, nearly fried bottom, as the butter browned and bubbled in the oven. (Also hard to say.)

At the end of the day, the most beautiful biscuits were made from an egg-rich batter and baked at 425° F. But I'd gladly eat any (and all) of them.

What's your biscuit preference and go-to recipe? Tell us in the comments below.