1/4 cup olive oil
3 yellow onions peeled and sliced
1/4 cup sherry vinegar
1/2 cup balsamic vinegar
1/2 cup water
1 teaspoon sugar
1/4 teaspoon piment d’espelette pepper or hot paprika pepper
Heat the olive oil in a heavy sauce pan over medium heat. Add the onions and saute until golden brown, about 10 minutes. Add the rest of the ingredients and bring to a bowl. Lower the heat and cook on a high simmer until the liquid is evaporated, about 30 minutes, maybe longer.