The cut parts of the artichokes are rubbed with lemon juice, place in boiling salted water to which are added a few drops of vinegar, and cook about 20 minutes. Leave to cool, remove secondary flakes and colored pistils. Finely chopped onion fry in sunflower oil, add the artichokes, vinegar and wine and stew until almost tender artichokes and the liquid evaporates, leaving only about 2 tablespoons. Add broth, garlic, black pepper and bay leaf and stew under the lid until the artichokes soften. Remove tender artichokes, the rest sauce Add flour, fry about one minute, stir and fry for another minute. Remove the garlic and bay leaf and serve immediately.