Photo: Tirachard Kumtanom (Shutterstock)
Some recipes are easy to cut in half or in thirds; one cup of sugar becomes a half, or a half a teaspoon of baking powder becomes 1/4 teaspoon. And then, there’s the egg—the one thing that math can’t really split. If you have a cookie or cake recipe that you’re trying to small batch in half, or by thirds, and there’s an odd egg out, you need to grab a whisk.
The most reasonably accurate way to divide a single egg is to scramble it up and pour it out. Scrambling the egg well will break up the membranes so the yolks and white can combine evenly. You’ll get a more accurate ratio of egg representation, and with the membranes broken, you’ll be able to stop the flow more accurately when you pour. Pour out exactly how much you need for your recipe using a kitchen scale to weigh it.
Depending on where the recipe was written, recipes refer to the average egg size in that particular country. In the U.S., that would be a large egg, but in the UK, a recipe will refer to a medium egg (there’s a helpful chart here). Assuming you’re in the U.S., large eggs weigh about 2-2.2 ounces each, sans shell. Luckily, this number makes splitting a recipe in half pretty easy. If you’re off by half an ounce, your recipe will turn out just fine.
Try to avoid using one part of the egg as “half.” It may be tempting to skip the scramble and just use the yolk, or the white, but egg yolks are heavier and, maybe more importantly, they each provide different qualities to baked goods. Egg yolks add richness, density, and dryness, while the whites can aerate, gel, and dry out surfaces. Adding an extra half yolk to a cookie recipe could make the final product more powdery, while too much egg white could lead to flatter (and shinier) cookies. Have I done this in haste before? Most definitely, and I lived to regret it. I really screwed up a Finnish pulla bread once. It was supposed to have a sweet cheese center, and suffice to say, it was a mess.
There are some recipes where it doesn’t matter, like pancakes. It matters, but it doesn’t matter. Sometimes you make pleasant discoveries this way. Maybe in 10 years your family’s secret waffle recipe will use one extra egg white. But if you’re putting in work to make something, you might as well do it right. Keep in mind, too, that the smaller the batch, the more vital an accurate egg measurement will be.
