Preparation 15 min
Cooking time 10-15 min
- In a large frying pan, heat the olive oil and butter over medium-high heat. Add the cipollini onions and cook for 1 to 2 minutes on each side until golden brown.
- Incorporate the white wine vinegar, both sugars, salt, peppercorns, and bay leaves. Cook for 1 to 2 minutes until the sugars have dissolved.
- Pour the balsamic vinegar, cover, and reduce the heat to medium-low. Cook until the onions are fork-tender, 8 to 12 minutes. Set aside to cool.
- Once cooled, transfer the onions to a heatproof container. Refrigerate and use within two weeks.