salt & freshly ground black pepper
- In a large saucepan, heat oil and butter over medium heat.
- Stir in onions, vinegar, sugar, bay leaf, and thyme.
- Cover and cook, stirring occasionally, until onions are tender, about 15 minutes.
- Remove lid, increase heat to medium high and cook until golden brown, stirring often, about 15 to 20 minutes.
- Season with salt and pepper and let cool to room temperature.