These may be the most versatile pickles you can make. "They're a natural for sandwiches, and of course burgers, but they're also great with smoked fish," says chef Renee Erickson, owner of several Seattle restaurants and of Boat Street Pickle company. You can use this brine for asparagus, fennel, shallots, garlic, celery, ramps, or chard stems.
2 cups organic distilled white vinegar or white-wine vinegar
1/4 cup sugar, preferably unbleached organic
1 tablespoon black peppercorns
2 sprigs fresh rosemary (about 3 in. long), divided
2 teaspoons fine sea salt
2 medium red onions (8 to 10 oz. each), peeled, sliced crosswise into 1/2-in. rings
How to Make It
Wash a wide-mouth 1-qt. canning jar and lid in hot, soapy water and rinse well. Set a round metal rack or a few biscuit cutters in a stockpot, fill with water, and bring to a boil. Lower jar into water, add lid with ring, and boil for 10 minutes. Reduce heat to a simmer and keep jar and lid in water until needed.
Put vinegar, 2/3 cup water, sugar, peppercorns, 1 rosemary sprig, salt, and onion in a large, non-reactive saucepan. Bring to a boil, covered. Reduce heat and simmer, covered, until onions turn pink and somewhat translucent and tender, 10 minutes. They should be neither stiff nor floppy; they'll soften more after the heat is turned off. If brine doesn't cover onions, turn slices occasionally so they all get cooked evenly.
Put fresh rosemary sprig in jar and set a wide-mouth funnel in neck of jar. (If you plan to keep the pickle for more than a week, skip the rosemary here--it will get too strong over time.) Discard rosemary from pot and add onions to jar. Pour in brine, leaving about 1 in. airspace at top. Stir in remaining peppercorns.
Close the lid just until tight. Let the pickles cool to room temperature, and then chill at least overnight before eating and preferably 1 week.