PREPARATION

Peel the onions and pour whole in a large skillet in which you have put to heat the oil with the butter; season with salt and pepper and let cook for about 10 minutes stirring frequently.

At this point add the chopped bacon and sprinkle with vinegar let it evaporate, then lower the heat, cover and cook for another 30 minutes.

If you were too dry, sprinkle again with a little hot water.

Serve with a generous sprinkling of pepper.