SAUCE: Discard the cooking oil and cool the pan slightly, then analyze the pan residue. A very dark brown, sticky fond is fine; if the fond is black, crumbly, or flaky, wipe the pan clean before proceeding. Return the skillet to medium heat and add a little fresh oil if the pan is very dry. Sauté the onions until tender and browned, about 2 minutes. Add the garlic and chile flakes and cook until the aroma blooms, about 20 seconds. Stir in the chopped artichokes, peppers, and oregano, then stir in the vinegar, being careful to avoid the fumes, or they may make you cough. Use a wooden spoon to dissolve any brown residue on the bottom of the pan. Add the vermouth, increase the temperature, and simmer until the raw aroma of alcohol is cooked off and the liquid has reduced by half.