How to halve an egg (yes, really)

Halving a three-egg cake leaves you owing the bowl one and a half eggs, and eggs do not crack in halves. The solution is the kitchen-math move that fixes most scaling problems: stop thinking in objects and think in grams.

What an egg weighs

US egg sizing is set per dozen, but the per-egg averages are consistent enough to cook by:

So half a large egg is 25 g, and “1½ eggs” means one whole egg plus 25 g of a second.

The method, with a scale

1. Crack the egg into a small bowl or mug.
2. Whisk with a fork for 15–20 seconds until the streaks of white disappear and the color is uniform. This matters: unmixed, you might pour off mostly white and bake with mostly yolk.
3. Set a second bowl on the scale, tare to zero, and pour in 25 g.

No scale? Use spoons

A whisked large egg measures about 3 tablespoons. Half is therefore 1½ tablespoons (1 tablespoon + 1½ teaspoons) — close enough for cookies, pancakes or quick breads. For delicate sponge cakes and macarons, use a scale; those recipes count grams of egg for a reason.

Why not “just use the yolk” or “just use a small egg”?

Whites and yolks do different jobs — whites set structure, yolks carry fat and emulsify — so substituting one yolk (18 g, all fat and lecithin) for half an egg (25 g, balanced) nudges a batter richer and denser. Sometimes pleasant, but it is an edit, not a halving. A “small” egg is a real option when the recipe is forgiving: at ≈ 38 g it overshoots half by 50%, fine in pancakes, risky in a lean cake.

The other half is an ingredient, not waste

• Egg wash — 25 g of beaten egg plus a teaspoon of water glazes a whole tray of pastry.
• Tomorrow's scramble — store covered in the fridge and use within 2 days, as you would any raw beaten egg.
• Freeze it — beaten egg freezes fine in an ice-cube slot for about a month; thaw in the fridge and whisk again before using.