Makes one jar for the refrigerator, about 1½ cups; adapted from David Lebovitz
Ingredients
3/4cupwhite vinegar or white wine vinegar
3tbspgranulated sugar
1pinchsalt
1red onion, peeled, halved and thinly sliced into half-rings
6whole black peppercornsoptional
6whole clovesoptional
Instructions
In a small saucepan, heat the vinegar, sugar, salt, and optional spices until boiling. Add the onion slices, lower heat, and simmer for 30 seconds. Remove from heat and cool completely. Transfer onions and liquid to a glass jar with lid and refrigerate.