A young onion harvested before the bulb swells, sold in bunches with a slim white base and long hollow green tops. The two halves behave completely differently.
What it does in a recipe: A dual-purpose allium — the whites give gentle raw onion flavour, the greens give a fresh finishing note and colour. Pick the swap that covers that job — the ratios below are written so you can act on them without doing any arithmetic.
Also called: Green onion, Spring onion, Salad onion
1 scallion (about 2 tbsp sliced) = 1 1/2 tbsp very thinly sliced red onion
You need slightly less because red onion is more pungent than a scallion white, but it holds the same crisp-raw quality.
Trade-offStronger and crunchier, and it will not give you the green ribbons a scallion garnish is partly there for.
Raw / no-cookCookingVeganVegetarianGluten-freeDairy-freeEgg-freeNut-freeSoy-freeAlcohol-free
Worth knowing
The greens wilt within seconds of hitting heat. If a recipe calls for scallions both in the cooking and on top, slice the whole bunch, then keep the greens aside until serving.
Cooking around an allergy? Diet tags here describe the ingredient itself, not any particular brand. Processed products change formulation without notice and shared production lines are common, so read the label on everything you use. A severe allergy is a medical matter — confirm with the manufacturer or your clinician rather than relying on a substitution chart.