When used as a base ingredient in a stir-fry or salsa, a fine rough chop will do you just fine. But the beauty of scallions is that they're as pretty as they are flavorful—provided you know how to cut them.
Here are the basic knife skills you'll need to produce three different types of garnish-worthy scallion slices.
Scallions, like other delicate vegetables and herbs, should be cut using a slicing motion as opposed to chopping. When you chop, you move your knife up and down with very little horizontal motion. This can cause crushing or bruising. Slicing using the full length of the blade and minimal downward pressure creates the cleanest cuts.
Here's a good rule of thumb: the more you can hear yourself slicing, the more you're crushing those poor scallions. A good, clean slice with a sharp knife should be nearly silent.
The best way to do this? A cut called the back-slice. Here's a quick video demo:
To apply it to scallions, start with with a relatively small bunch of scallions—three to four at most—and unless they're extremely fresh and firm, lay them out in a single layer, rather than stacking.
Place the tip of the blade against the cutting board with the flat of the blade resting against your knuckles.
Hold the knife at a very low angle and pull backwards steadily, using the entire length of the blade to slice through the scallions, with no downward motion at all.
Continue pulling backwards until the tip of your blade slices completely through the scallion.
Remember: NO DOWNWARD MOTION WHATSOEVER! The idea here is maximum horizontal motion (i.e. slicing) with minimal vertical motion (i.e. crushing).
Depending on the angle at which you hold the scallion, you can get different shapes, ranging from circles to long, slender ovals.
If you cut at an extreme oblique angle, or even slice parallel to the length of the scallion, you can create ultra-fine scallions "hairs" that make a great addition to salads or work as a garnish for your ramen or grilled meats.
The process is the same as with the back-slice: just hold the scallions nearly parallel to the blade. You may have to crush them a bit with your steadying-hand in order to get them to slice cleanly, but don't worry, there's an easy way to revive them.
Store the sliced scallions in a container of ice water in the fridge for at least 30 minutes and up to overnight, and they'll absorb liquid, firming up and curling into pretty little threads. (An added benefit of storing the sliced scallions in cold water, at least for those who are sensitive to raw onion flavor, is that it will temper their potency a little, resulting in crisp, fresh, and milder tasting scallions.)
You ever order Peking duck at a Chinese restaurant and get served a bowl of hoisin sauce with some cute little scallion brushes to paint the sauce onto your pancakes? Those little brushes are super easy to make at home.
Start by trimming down your scallion to about 2 1/2-inches long.
Trim off the root end as close as you can to the base.
Holding the scallion steady with your non-knife hand, align your knife parallel to the scallion and place the tip of your blade about an inch up from the cut side. Cut through to split the the end of the scallion in half.
Repeat the process, rotating the scallion a few times so that you've made a total of four cuts, dividing the scallion-end into 8 individual sections.
Transfer the brushes to a bowl of ice water in the fridge and let them soak for at least 30 minutes and up to overnight to get them to firm up and curl.
The first step to great food is great knife skills. Check out more Knife Skills this way!