Sweet and Sour Onions (Cipolline en Agrodolce)

These sweet and sour onions make a great appetizer or side dish.


  • 2 pounds cipolline onions, peeled and left whole
  • 3 Tablespoons butter
  • 1 1/2 teaspoons kosher salt
  • 1/2 cup balsamic vinegar
  • 1-2 Tablespoons sugar


  • Bring water to boil in a saucepan large enough to hold all the onions. When the water starts boiling, add the onions, bring back to a boil and cook until tender, about 20 minutes. Use a small paring knife to pierce them and make sure they're soft all the way through. Drain the onions in a colander.
  • Heat the butter in a large heavy skillet over medium-high heat. Add the onions and stir to coat them with butter. Season with salt and cook, stirring frequently, until caramelized, about 5 minutes.
  • Add the vinegar and sprinkle the sugar over the onions. Shake the skillet back and forth to make the onions roll around a bit. Bring the vinegar to a boil and cook another 5 minutes, until the syrup thickens slightly.
  • Serve warm or at room temperature with the syrup drizzled over the onions.