Egg allergy

An egg allergy is a reaction of the immune system to proteins in egg. Both the white and the yolk contain them. It is one of the most common food allergies in young children, and it is a labeled allergen in both the EU and the US. Eggs from duck, goose and quail are similar, so they are usually avoided too.

Some people with an egg allergy can eat egg that is well baked into a cake while others cannot. Only an allergist can tell you which applies to you, so do not test this at home.

Substitutes

These replace one egg in most baking:

• 45 ml (3 tablespoons) aquafaba, the liquid from a can of chickpeas. It whips like egg white for meringues.
• 1 tablespoon ground flaxseed mixed with 3 tablespoons water and left for 5 minutes. Best in muffins, cookies and quick breads.
• 60 g (1/4 cup) mashed banana or applesauce. It adds moisture and some flavor.

For an egg wash, brush pastry with plant milk or a little oil instead. For mayonnaise, use an egg-free version made with aquafaba or soy milk.

Swaps work best in recipes that use one or two eggs. A dish that depends on eggs, such as a soufflé or custard, rarely works well with them.

Common mistakes

• Missing egg in fresh pasta, noodles, meatballs, breadcrumb coatings and batters.
• Forgetting sauces built on egg yolk, such as aioli, hollandaise and béarnaise.
• Assuming "egg substitute" is egg-free. In the US many products sold that way are made from egg whites.
• Assuming a shiny bread crust is just butter. It is often egg wash.

In recipes

Eggs bind, lift, set and glaze, so they are in more dishes than you might expect: cakes, cookies, pancakes, waffles, custards, ice cream, marshmallows, meringue toppings and many glazed breads. In the EU and the UK, egg must be emphasized in the ingredients list. In the US it is named as "egg" in the ingredients or a "Contains" statement. Read labels every time you buy, ask in restaurants, and talk to a doctor about what to do if you eat egg by accident.