Step 1 In a medium bowl, combine the onion, preserved lemon, garlic, parsley, dill and chile flakes. Add the Champagne vinegar and mix well to evenly distribute. While whisking, slowly drizzle in the oil. Season to taste with the salt and pepper. This makes a scant cup vinaigrette, more than enough for the remainder of the recipe. The vinaigrette will keep, covered and refrigerated, for up to 5 days.