Cheap vinegar, produced from inferior red wine, will give poor results to your finished dish. Buy good quality, aromatic vinegar with a complex flavour. The label will often specify which type of ...
Meanwhile, bring the red wine vinegar and sugar to the boil, stirring to dissolve the sugar. Simmer until slightly thickened. Pour over the shallots and leek and garnish with rosemary sprigs.
Add red wine vinegar to the pan ... In a larger, deeper pan medium heat, add white onion or shallot and a splash of extra-virgin olive oil. Cook until soft, about 4–5 minutes.