Pickled onions such as these are most often used as a garnish for tacos, burritos, and guacamole in Mexican cuisine. I think they are just as delicious on most of the burgers in this book, and they add a level of intrigue that raw onion slices could never do. The fresh lime juice is essential for its fresh, clean flavor as well as its acidity. If you want to pump up the volume on flavor and add a bit of heat, try adding a few whole jalapeño or serrano chiles to the mix.

　　

Ingredients

Makes about 2 cups

　　1 cup fresh lime juice

　　1/2 cup distilled white vinegar

　　1 tablespoon sugar

　　2 teaspoons kosher salt

　　2 large red onions

　　2 teaspoons finely chopped fresh oregano leaves

　　2 whole serrano chiles or jalapeño chiles, slit down the center (optional)

　　

Step 1

Whisk together the lime juice, vinegar, sugar, and salt in a medium nonreactive bowl and let sit until the salt and sugar dissolve, about 5 minutes.

　　

Step 2

Meanwhile, peel and halve the onions, and then cut into 1/8-inch-thick slices. Add the onions, oregano, and chiles, if using, to the lime juice mixture and stir well to combine. Cover and refrigerate for at least 24 hours and up to 2 days, stirring the mixture at least once during this time. Drain before serving.

　　Bobby Flay's Burgers, Fries, and Shakes