Tomato Onion Salad

This no-fuss tomato onion salad turns those two everyday vegetables, and a few other pantry staples, into a memorable starter or side dish. Unlike an ordinary green salad with tomato and onion, this one makes the duo the stars of the show.

It’s especially good when you’re using the ripest and tastiest of tomatoes. But don’t let that stop you from making this salad year-round, because the dressing can liven up even mediocre, mid-winter tomatoes. The sweet onions are a nice touch, and we have lots of other sweet onion recipes to help you use up the rest of the bag.

Ingredients for Tomato Onion Salad

• Tomatoes: Sliced ripe tomatoes are juicy, with a nice balance of tart and sweet.
• Sweet onions: Sweet onions provide a mild, sweet version of onions’ pungent flavor. They make a wonderful complement to the tomatoes, both in your mouth and on the plate.
• Olive oil: Olive oil is a heart-healthy choice for the oil element in the salad’s dressing.
• Red wine vinegar: Red wine vinegar gives the salad’s dressing a bold flavor and acidity. If your tomatoes aren’t the best, it will also help liven them up.
• Parsley: Chopped parsley brings a bright pop of contrasting color to the salad. It also helps bring out the flavors of the other ingredients.
• Italian seasoning: The herbs that make up Italian seasoning—basil, oregano, bay leaf, sage and sometimes a few others—all complement tomatoes beautifully.
• Chopped onion: A small quantity of chopped regular onion provides a more pungent onion note to complement the sweet onions in the salad.
• Sugar: Sugar provides some sweetness to balance the vinegar’s acidity and also (like the vinegar) can help elevate the flavor of tomatoes that aren’t at their best.
• Garlic powder and black pepper: The final seasonings in the dressing, garlic powder and black pepper, help round out its flavors.

Directions

Step 1: Arrange the tomatoes and sweet onions

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Layer the sliced tomatoes and sweet onions in a shallow serving dish.

Step 2: Dress the salad

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In a jar with a tight-figging lid, combine the olive oil, red wine vinegar, minced parsley, salt, Italian seasoning, chopped onion, sugar, garlic powder and pepper, and shake the jar well to mix them. Drizzle the dressing over the salad. Cover the salad and refrigerate it for at least two hours before serving.

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Tomato Onion Salad Variations

• Use different tomatoes: Using large rounds of tomato and big rings of sweet onion gives the salad its visual appeal, but you can scale things down if you wish. Instead of using big slicing tomatoes, go with halved cherry or grape tomatoes instead. You can still use the big rings of sweet onion, because the contrast between those and the small tomatoes lends visual interest. Alternatively, switch to shallots for a sweet onion flavor that’s a closer match in size.
• Swap the tomato for avocado: Avocados aren’t as flavorful as tomatoes, but they’re a surprisingly good alternative in this salad. You can use the same vinaigrette and technique, or you can use the alternative dressing in this avocado and onion salad.
• Opt for an onion and cucumber salad: Tomatoes and cucumbers are at their peak during the same time of year. If you’re a gardener or farmers market fan, you’ll want ways to make use of them both. One option is to replace the tomatoes in this recipe with sliced cucumbers. You can use the English or “burpless” style whole; for field cucumbers, it’s best to peel the skin. Replace the red wine vinegar with white wine vinegar, and you’re off to the races. We do have a different cucumber and onion salad on the site, but it uses strong white vinegar and it’s more of a marinade or quick-pickle.

How to Store Tomato Onion Salad

Any salad that’s left over should be covered and returned to the fridge. Alternatively, rather than refrigerating the serving platter, transfer the salad to a glass or plastic-food storage container with a tight-fitting lid.

How long will this tomato and onion salad keep?

The tomatoes are the weak point in this salad, because they’ll start to soften and lose their texture rather quickly. The salad’s storage life depends on the type of tomato you’ve chosen and how ripe it was, but you should plan to eat up any leftovers within a day or two.

Can I make this salad ahead of time?

The salad needs to chill for at least two hours in order for the flavors to fully develop. You could stretch that to preparing as much as a day ahead of time, unless the tomatoes are dead ripe. In that case, it’s best not to make the salad more than six to eight hours ahead.

Tomato Onion Salad Tips

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What type of tomatoes should I use for this recipe?

The short answer is “big ones,” because the salad looks best with generously sized slices. Most beefsteak-style slicing tomatoes work just fine. Even in mid-winter, when store-bought tomatoes are pretty lifeless, the dressing will help perk them up. You’ll get the best flavor with ripe tomatoes from your garden or farmers market, and especially with heirloom tomato varieties.

I find small tomatoes are tastier during the offseason, can I use those?

You’re not wrong. Commercial tomatoes are bred to stand up to shipping and handling. Big tomatoes have a lot more squishy insides because of their size and weight, so they’re fragile. Growers pick them while they’re underripe, then promote further ripening with ethylene gas. That sounds worse than it is; you do the same when you ripen avocados with an apple or banana (they produce it naturally). Smaller grape, cherry and cocktail tomatoes are innately sturdier because of their small size. That means they can be picked when they’re closer to full ripeness, and therefore tastier.

Can I use regular onions instead of sweet onions?

Yes, you certainly can if you don’t have sweet onions on hand (or if they’d bend your budget). Red onions are mild enough to use as is, though they don’t look as good on the red tomatoes. Alternatively, you can thin-slice regular white or yellow onions, and dunk them for a few minutes in cold water to tame their pungent bite.