My grandmother relied on this cooling summer staple during the hardest years. Taking only 3 ingredients, it provides a bright crunch that is surprisingly comforting on a hot day.

This 3-ingredient cucumber onion salad is the kind of cooling summer staple that shows up when times are lean but the garden is generous. My grandmother leaned on this simple bowl of crisp cucumbers, sharp onion, and a light vinegar brine during some of the hardest years of her life in the rural Midwest. With no oil, no sugar, and no extras, it’s all about bright crunch and clean flavor—surprisingly comforting on a hot day, especially when it’s made ahead and served straight from the fridge.

Serve this salad icy cold, straight from the refrigerator, as a side to grilled chicken, sausages, or simple pan-fried pork chops. It cuts nicely through richer dishes like bratwurst, burgers, or creamy casseroles, and it’s especially good next to anything smoky from the grill. For a lighter meal, pair it with sliced tomatoes, a hunk of crusty bread, and a bit of cheese. It also travels well in a chilled container for picnics or potlucks, provided it stays cold.

Servings: 4

4 cups thinly sliced cucumber (about 2 large cucumbers)

Prepare the vegetables: Rinse the cucumbers under cool running water and pat them dry. If the skins are thick or waxy, peel them; otherwise you can leave the skins on for extra color and crunch. Slice the cucumbers into very thin rounds, about 1/8 inch or thinner if you can, using a sharp knife or mandoline. Place the slices into a medium glass mixing bowl.

Slice the onion: Peel the white onion and slice it as thinly as possible into half-moons or rings. You want delicate, almost translucent slices so they soften slightly in the vinegar while still keeping a bit of bite. Add the sliced onion to the bowl with the cucumbers and gently toss to loosely combine.

Add the vinegar: Pour the distilled white vinegar over the cucumbers and onions. The liquid will not completely submerge the vegetables at first, but as they sit they will release some of their own juices and create more brine. Use clean hands or a spoon to gently toss everything so the vinegar lightly coats all the slices.

Chill and marinate: Cover the glass bowl tightly and refrigerate for at least 30 minutes, preferably 1 to 2 hours. During this time, the cucumbers and onions will soften slightly, release liquid, and take on a bright, tangy flavor. For more even marinating, give the salad a quick toss once or twice while it chills.

Serve: Just before serving, toss the salad again to redistribute the vinegar and the now slightly increased amount of liquid in the bowl. Taste a slice of cucumber; if it’s too sharp for you, you can splash in a tablespoon or two of cold water to soften the acidity, but keep in mind that the classic version is quite bright. Serve cold, making sure each portion gets both cucumbers and onions with a bit of the clear, tangy liquid spooned over the top.

Store: Keep any leftovers covered in the refrigerator for up to 2 days. The cucumbers will continue to soften as they sit in the vinegar, but the flavor will deepen. Always use a clean utensil when serving to help the salad stay fresh as long as possible.

This salad is intentionally spare—just cucumbers, onion, and vinegar—because that’s how many Midwestern families stretched garden produce during tough years. If you’d like to stay close to tradition but adjust to modern tastes, you can dilute the vinegar slightly with cold water (up to 1/4 cup) for a gentler tang, or sprinkle a small pinch of salt right before serving to heighten the flavors without changing the core recipe. For a slightly different character, you can swap in apple cider vinegar or white wine vinegar, but distilled white vinegar gives the clearest, brightest brine that matches the classic look and flavor. If you want a bit of sweetness, you can dissolve a teaspoon or two of sugar into the vinegar before adding it to the vegetables, though that does move away from the austerity of the original. Food safety tips: Always wash cucumbers and onions under cool running water before slicing, and use a clean cutting board and knife. Because this recipe is not heat-processed or canned, it must be kept refrigerated; do not leave the salad out at room temperature for more than 2 hours (or 1 hour if it’s above 90°F). Store in glass or other non-reactive containers, since straight vinegar can be harsh on some metals. Discard the salad if it develops off smells, sliminess, or any signs of mold. If slicing with a mandoline, use the hand guard or cut-resistant glove to protect your fingers from the very sharp blade.