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Theresaasks via Twitter:

Hi, Theresa,

There is no single answer to this question, because an egg does so many things in baking and cooking. Reducing an egg for one recipe may make perfect sense, but completely wreck another recipe. So, let’s look at the egg, what it does, and what we can do with it.

What an egg does:

• Emulsifier – an egg contains lecithin,which will bring water and oil together.
• Fluff – whipped egg whites will add body and air to a dish.
• Structure – eggs will create a stable matrix of molecules to cause custards of various types to retain their shape.
• Moisture – eggs contain fats which make baked goods moist.
• Drying –egg whites will tie up water molecules, reducing the moisture level of a baked good.
• Flavor – eggs are tasty.

This is not a complete list, per se, but a good representative sample of the common things that an egg will do in most of the dishes you’re likely to see. So, let’s examine a few possibilities.

If you need the whole egg in a recipe, the easiest way to halve it is to mix together the eggs and whites thoroughly and pour half of the mixture into another vessel. You can keep this for a day or so, but you’re best off just making somescrambled eggswith it.

If you need just the yolk, you can separate the white from the yolk and mix and halve the yolk as above. The white can be frozen into a yolk-cube for long-term storage, or you could mix it with the rest of the egg yolk for a less-fatty scrambled egg.

If you need the egg whites for foam, just whip the full amount of egg white and use half of it, or even a bit more.

Use the whole egg. You may have noticed that the above descriptions were not terribly exact as far as measurements and how much to use. This is becauseeggs are not precisely measured packagesin small amounts. If you’re making something with dozens of eggs or more, then chances are that you’ll weigh your eggs, because the variation in egg over dozens or hundreds of eggs may shift more than your quality assurance folk prefer, and consequently may affect the final product.

For home use, though, I rarely weigh my egg amount, even if I weigh all of the other ingredients. Even if I did, each egg is going to have a different proportion of yolk to white, and I wouldn’t be surprised to discover that the chemical makeup of each egg is going to be somewhat different from chicken to chicken or breed to breed, or even based on what the chicken was eating that week.

Any recipe you use, unless it’s some sort of fancy molecular gastronomical recipe, is going to have enough play in it to allow for a pretty wide deviation in egg amount. You’re likely to find that whatever you’re making is going to be more rich than if you used half the egg, but it’s probably not going to be the worse for wear.

Theegg nog recipe I useis an example of this: I’ve modified it so that all of my ingredients work out in even units if I make a triple batch, which I usually will (2/3 for use with bourbon, 1/3 with no distilled spirit). That uses 2 dozen eggs, and all of the milk and cream works out to whole cartons in the end. The original recipe did not work so well from a shopping standpoint, but custards, especially ones that aren’t cooked, are plenty malleable.

Of course the final option is to just make the whole recipe and give half of it away to friends, family, and co-workers. If you’re making a cookie dough or similar, you could even freeze half of it and save it for later. The important thing is that you have plenty of options to suit your situation. A versatile ingredient lends itself to a versatile workflow.