It’s all in the onions.

Who doesn’t love classic Italian-American-restaurant salads? We all have fond memories of meals at those old-fashioned, red-sauce palaces: The service is warm and parental, portions are enormous, and the house salad comes with a pile of crisp iceberg lettuce, tomatoes, cucumbers, whole pickled pepperoncini peppers, croutons made from yesterday’s leftover bread, and thinly sliced raw red onion, all in a simple, sweet red wine vinaigrette that's heady with oregano.

Those salads are a thing of beauty, and I wanted to be able to make them at home. But every time I tried to replicate them, I found that using a raw onion overwhelmed the plate and marred that nostalgic, perfect flavor.

But here’s the secret: If you marinate the onion just a little bit (a personal trick I developed because I’m not a fan of raw onions in any dish), it tunes the plate to perfection. It’s as simple as popping a candlestick in a Chianti bottle.

How to Make Classic Italian Restaurant Salad Dressing

1. Take one small red onion (or half a big one), cut into quarters, and slice thinly. You want little strips that will fit on a fork, not minced or diced. Think of the onion as a visible ingredient in the salad.

2. Rinse the cut-up onion under cold water to remove some of the extra bite. Pat dry with paper towels.

3. Place slices in a small bowl or in a jar and sprinkle with a couple good pinches of Kosher salt and a couple of granulated sugar, five or six grindings of fresh black pepper, and about a tablespoon of dried oregano. Toss them to coat.

4. Press the onions down in your bowl or jar to compress them and pour red wine vinegar over them to almost the top (some onions will be poking up out of the vinegar).

5. Add olive oil on top to about equal the amount of onion vinegar mixture (do this by eye, you’ll adjust flavors later). Give a good stir or shake and let sit covered at room temp for a minimum of four hours to overnight. The onions should turn a translucent purple.

6. Give the dressing a good stir or shake and taste, adjusting the seasoning to your preference of salt, sweet, peppery, or oregano. If you think it tastes too oily, add more vinegar; too sharp, add more oil.

And you’re ready to indulge in perfect Italian salad. Cue “O Sole Mio!"

Insider Tip: This technique is easily adaptable to create other styles of dressing. Swap in lemon juice for red wine vinegar for a Greek style or remove the oregano and add some Dijon for a French flair. Use balsamic, white wine, sherry or apple cider vinegar for different flavorings as well. Use scallion instead of red onion, rice wine vinegar, and add some ginger and sesame oil and you have a version that is a little bit Asian.