Ingredient

Spring onion

A spring onion is not one ingredient. The white bulb behaves like a mild onion and wants cooking; the dark green tops are a herb and want adding at the end; and the pale middle sits between the two. Treating the whole bunch as one thing is why spring onions so often end up as a limp garnish rather than doing any work.

The three parts

The white bulb

Mild onion. Cook it — it wants heat, and it will soften and sweeten like a small shallot. Slice it and start it in the pan with the other aromatics.

The pale green middle

Between the two. Crunchy raw, softens quickly cooked. Good in both directions.

The dark green tops

A herb, not an onion. Grassy, fresh and delicate, and heat destroys it. Add raw, or in the last thirty seconds. Cooked from the start it turns slimy and drab.

The roots

Trim them off, but keep them if you like — planted in soil or stood in water they regrow, which is the one genuinely reliable kitchen-scrap regrowing trick.

Cutting matters more than usual

The shape you cut a spring onion into changes what it does on the plate.

• Fine rings — the default. Even distribution, mild effect, good on almost anything.
• Diagonal slices — more surface, more visual presence, more crunch. Standard in stir-fries.
• Long shreds, cut lengthways — dropped into iced water they curl dramatically, and they stay crisp for hours. This is the classic garnish for Peking duck and for Korean grilled meat.
• Whole, halved lengthways — grilled or charred until soft and blackened at the edges, which is a dish rather than a garnish. Excellent on a barbecue.
• Separated white and green — the professional habit worth adopting: two piles, used at two different moments.

Ways to use them

• In stir-fries, whites in early with the ginger and garlic, greens thrown in at the end.
• Charred whole on a griddle or barbecue with olive oil and salt, or with romesco. Spring onions treated as a vegetable in their own right are badly underrated.
• In spring onion pancakes — laminated flatbreads with the greens rolled through them.
• Raw on almost anything — soup, dal, noodles, rice, eggs, tacos, potatoes. They provide the fresh green note a cooked dish has lost.
• In a scallion oil. Sliced greens covered in hot oil so they sizzle, then cooled. Keeps for days and is one of the most useful things in a fridge.
• In dips and dressings, blended into yoghurt, soured cream or mayonnaise.
• In place of chives, which they are close relatives of and can generally stand in for.

Buying and keeping

Look for firm white bulbs and green tops that are upright and unblemished rather than slimy at the tips. Spring onions deteriorate from the green end down, so limp tops on a firm bulb means an older bunch that is still usable.

They keep about a week in the fridge, and they keep better standing in a jar with a little water than lying in a bag — the same as a bunch of herbs. Wrapping them in a damp cloth also works.

Freezing works surprisingly well for the greens: sliced and frozen in a bag, they go straight into a hot pan or a soup with no thawing. The texture is gone but the flavour is not, and it is a good answer to a bunch about to turn.

Common questions