Using raw onions as a garnish can be polarizing. But that's because they often taste awful. Too many times, good, honest people have been scourged by the pungent, sulfuric bite of uncooked onions: in rings on top of an otherwise decent burger, chopped and sprinkled over a fish taco that they almost liked, sliced and tangled with greens in the most disappointing salad.
But it needn't be so. That sharp taste that comes from slicing into an onion can actually be washed away—quite literally—leaving behind a crisp, cool, sweet bite that actually complements the dish you're adding it to. The proverbial wisdom has always held that a 10- to 30-minute soak in ice water is necessary to mitigate that bitter heat; but in the Test Kitchen we've found that a mere 60-second rinse under cold running water will suffice.
After a quick rinse, crisp raw onions are ready for your noodle bowl.
Senior food editor Anna Stockwell says the quick rinse will make the sliced onions taste "sweeter and less sharp" than onions that haven't undergone the same treatment. Another bonus: the cold water will make the onions exceptionally crisp. Which is the real reason she added them to her recent weeknight dinner recipe of caramelized pineapple and shrimp tossed in a sweet, sour, spicy sauce.
With the dish's briny, tender shrimp and juicy, soft pineapple, Anna was looking for something that could add a fresh bite and crisp textural counterpart. Raw sliced red onions, with their satisfying crunch and hint of heat, were the answer.
Here's how to quell the pungent bite of sliced onions in your own kitchen:
1. Slice the onions
Follow the technique here for slicing onions from pole to pole instead of horizontally. This technique results in onions that are more uniform, which in this case is mainly for aesthetics, but will also make it easier to transfer onions from place to place.
2. Place sliced onions in a sieve
If you have a colander with small holes, that will work too.
3. Hold the sieve under running water
Cold water is best for this—the colder the better—since warm water may soften the onions. As the water runs over the onions, shuffle them around with your free hand a few times to ensure every surface is thoroughly rinsed. Keep rinsing and shuffling for one to two minutes.
4. Dry the onions
Shake out the excess water; empty the onions onto paper or cloth kitchen towels and pat them dry.
5. Sprinkle onions on everything
Really. There aren't a lot of savory dishes that wouldn't benefit from crisp, sweet onions. Think tacos, pita sandwiches, salads, curries, even grilled fish.
And if you have any sliced onion left over, go ahead and store the slivers submerged in cold water in a resealable container in the fridge for a day or two. (After that you'll either want to cook them or toss them into the compost bin.) Because the only thing better than a quick onion garnish is one you didn't have to cry over.
